For thousands of years prior to the arrival of European settlers in North Georgia, the indigenous Creek people and their ancestors inhabited the area. Standing Peachtree, a Creek village where Peachtree Creek flows into the Chattahoochee River, was the closest Native American settlement to what is now Atlanta. Through the early 19th century, European Americans systematically encroached on the Creek of northern Georgia, forcing them out of the area from 1802 to 1825. The Creek were forced to leave the area in 1821, under Indian Removal by the federal government, and European American settlers arrived the following year.

In 1836, the Georgia General Assembly voted to build the Western and Atlantic Railroad in order to provide a link between the port of Savannah and the Midwest. The initial route was to run southward from Chattanooga to a terminus east of the Chattahoochee River, which would be linked to Savannah. After engineers surveyed various possible locations for the terminus, the "zero milepost" was driven into the ground in what is now Foundry Street, Five Points. When asked in 1837 about the future of the little village, Stephen Harriman Long, the railroad's chief engineer said the place would be good "for one tavern, a blacksmith shop, a grocery store, and nothing else". A year later, the area around the milepost had developed into a settlement, first known as Terminus, and later Thrasherville, after a local merchant who built homes and a general store in the area. By 1842, the town had six buildings and 30 residents and was renamed Marthasville to honor Governor Wilson Lumpkin's daughter Martha. Later, John Edgar Thomson, Chief Engineer of the Georgia Railroad, suggested the town be renamed Atlanta, supposedly a feminine version of the word "Atlantic", referring to the Western and Atlantic Railroad. (Atalanta was also Martha Lumpkin's middle name.) The residents approved, and the town was incorporated as Atlanta on December 29, 1847.

By 1860, Atlanta's population had grown to 9,554. During the American Civil War, the nexus of multiple railroads in Atlanta made the city a strategic hub for the distribution of military supplies.

In 1864, the Union Army moved southward following the capture of Chattanooga and began its invasion of north Georgia. The region surrounding Atlanta was the location of several major army battles, culminating with the Battle of Atlanta and a four-month-long siege of the city by the Union Army under the command of General William Tecumseh Sherman. On September 1, 1864, Confederate General John Bell Hood decided to retreat from Atlanta, and he ordered the destruction of all public buildings and possible assets that could be of use to the Union Army. On the next day, Mayor James Calhoun surrendered Atlanta to the Union Army, and on September 7, Sherman ordered the city's civilian population to evacuate. On November 11, 1864, Sherman prepared for the Union Army's March to the Sea by ordering the destruction of Atlanta's remaining military assets.

After the Civil War ended in 1865, Atlanta was gradually rebuilt during the Reconstruction era. The work attracted many new residents. Due to the city's superior rail transportation network, the state capital was moved from Milledgeville to Atlanta in 1868. In the 1880 Census, Atlanta had surpassed Savannah as Georgia's largest city.

Beginning in the 1880s, Henry W. Grady, the editor of the Atlanta Constitution newspaper, promoted Atlanta to potential investors as a city of the "New South" that would be based upon a modern economy and less reliant on agriculture. By 1885, the founding of the Georgia School of Technology (now the Georgia Institute of Technology) and the Atlanta University Center, a consortium of historically black colleges made up of units for men and women, had established Atlanta as a center for higher education. In 1895, Atlanta hosted the Cotton States and International Exposition, which attracted nearly 800,000 attendees and successfully promoted the New South's development to the world.

During the first decades of the 20th century, Atlanta enjoyed a period of unprecedented growth. In three decades' time, Atlanta's population tripled as the city limits expanded to include nearby streetcar suburbs. The city's skyline grew taller with the construction of the Equitable, Flatiron, Empire, and Candler buildings. Sweet Auburn emerged as a center of Black commerce. The period was also marked by strife and tragedy. Increased racial tensions led to the Atlanta Race Riot of 1906, when Whites attacked Blacks, leaving at least 27 people dead and over 70 injured, with extensive damage in Black neighborhoods. In 1913, Leo Frank, a Jewish-American factory superintendent, was convicted of the murder of a 13-year-old girl in a highly publicized trial. He was sentenced to death, but the governor commuted his sentence to life. An enraged and organized lynch mob took him from jail in 1915 and hanged him in Marietta. The Jewish community in Atlanta and across the country were horrified. On May 21, 1917, the Great Atlanta Fire destroyed 1,938 buildings in what is now the Old Fourth Ward, resulting in one fatality and the displacement of 10,000 people.

On December 15, 1939, Atlanta hosted the premiere of Gone with the Wind, the epic film based on the best-selling novel by Atlanta's Margaret Mitchell. The gala event at Loew's Grand Theatre was attended by the film's legendary producer, David O. Selznick, and the film's stars Clark Gable, Vivien Leigh, and Olivia de Havilland, but Oscar winner Hattie McDaniel, an African-American actress, was barred from the event due to racial segregation laws.

Atlanta played a vital role in the Allied effort during World War II. Colonel Blake Van Leer, the president of Georgia Tech, played a significant part by lobbying war-related manufacturing companies like Lockheed Martin to move to Atlanta, successfully lobbying the Government to build military bases, in turn helping attract thousands of new residents through new jobs. Van Leer also launched major research centers, which included Neely Nuclear Research Center and funds to help make Georgia Tech the "MIT" of the south while also founding Southern Polytechnic State University.

These new defense industries attracted thousands of new residents and generated revenues, resulting in rapid population and economic growth. In the 1950s, the city's newly constructed highway system, supported by federal subsidies, allowed middle class Atlantans the ability to relocate to the suburbs. As a result, the city began to make up an ever-smaller proportion of the metropolitan area's population.

African-American veterans returned from World War II seeking full rights in their country and began heightened activism. In exchange for support by that portion of the Black community that could vote, in 1948 the mayor ordered the hiring of the first eight African-American police officers in the city.

Much controversy preceded the 1956 Sugar Bowl, when the Pitt Panthers, with African-American fullback Bobby Grier on the roster, met the Georgia Tech Yellow Jackets. There had been controversy over whether Grier should be allowed to play due to his race, and whether Georgia Tech should even play at all due to Georgia's Governor Marvin Griffin's opposition to racial integration. After Griffin publicly sent a telegram to the state's Board of Regents requesting Georgia Tech not to engage in racially integrated events, Georgia Tech's president Blake R. Van Leer rejected the request and threatened to resign. Later, students from both Georgia Tech and the University of Georgia held a protest against Griffin's stance, which soon turned into a riot. The students broke windows, upturned parking meters, hung Griffin in effigy, and marched all the way to the governor's mansion, surrounding it until 3:30 a.m. Griffin publicly blamed Georgia Tech's president for the "riots" and requested he be replaced and Georgia Tech's state funding be cut off. On December 5 the Georgia Tech board of regents voted 13–1 in favor of allowing the game to proceed as scheduled.

In the 1960s, Atlanta became a major organizing center of the civil rights movement, with Martin Luther King Jr., Ralph Abernathy, and students from Atlanta's historically black colleges and universities playing major roles in the movement's leadership. While Atlanta in the postwar years had relatively minimal racial strife compared to other cities, Blacks were limited by discrimination, segregation, and continued disenfranchisement of most voters. In 1961, the city attempted to thwart blockbusting by realtors by erecting road barriers in Cascade Heights, countering the efforts of civic and business leaders to foster Atlanta as the "city too busy to hate."

Desegregation of the public sphere came in stages, with public transportation desegregated by 1959, the restaurant at Rich's department store by 1961, movie theaters by 1963, and public schools by 1973 (nearly 20 years after the US Supreme Court ruled that segregated public schools were unconstitutional).

In 1960, Whites comprised 61.7% of the city's population. During the 1950s–70s, suburbanization and White flight from urban areas led to a significant demographic shift. By 1970, African Americans were the majority of the city's population and exercised their recently enforced voting rights and political influence by electing Atlanta's first Black mayor, Maynard Jackson, in 1973. Under Mayor Jackson's tenure, Atlanta's airport was modernized, strengthening the city's role as a transportation center. The opening of the Georgia World Congress Center in 1976 further confirmed Atlanta's rise as a convention city. Construction of the city's subway system began in 1975, with rail service commencing in 1979. Despite these improvements, Atlanta lost more than 100,000 residents between 1970 and 1990, over 20% of its population. At the same time, it developed new office space after attracting numerous corporations, with an increasing portion of workers from northern areas.

Atlanta was selected as the site for the 1996 Summer Olympic Games. Following the announcement, the city government undertook several major construction projects to improve Atlanta's parks, sporting venues, and transportation infrastructure; however, for the first time, none of the $1.7 billion cost of the games was governmentally funded. While the games experienced transportation and accommodation problems and, despite extra security precautions, there was the Centennial Olympic Park bombing, the spectacle was a watershed event in Atlanta's history. For the first time in Olympic history, every one of the record 197 national Olympic committees invited to compete sent athletes, sending more than 10,000 contestants participating in a record 271 events. The related projects such as Atlanta's Olympic Legacy Program and civic effort initiated a fundamental transformation of the city in the following decade.

During the 2000s, the city of Atlanta underwent a profound physical, cultural, and demographic change. As some of the African-American middle and upper classes also began to move to the suburbs, a booming economy drew numerous new migrants from other cities in the United States, who contributed to changes in the city's demographics. African Americans made up a decreasing portion of the population, from a high of 67% in 1990 to 54% in 2010. From 2000 to 2010, Atlanta gained 22,763 white residents, 5,142 Asian residents, and 3,095 Hispanic residents, while the city's Black population decreased by 31,678. Much of the city's demographic change during the decade was driven by young, college-educated professionals: from 2000 to 2009, the three-mile radius surrounding Downtown Atlanta gained 9,722 residents aged 25 to 34 and holding at least a four-year degree, an increase of 61%. This was similar to the tendency in other cities for young, college educated, single or married couples to live in downtown areas.

In the lead-up to the 1996 Summer Olympics, the Atlanta Housing Authority demolished nearly all of its public housing. Residents instead received vouchers to pay for private housing; a wave of mixed housing was built using funding from the HOPE VI program under CEO Renee Lewis Glover (1994–2013).

In 2005, the city approved the $2.8 billion BeltLine project. It was intended to convert a disused 22-mile freight railroad loop that surrounds the central city into an art-filled multi-use trail and light rail transit line, which would increase the city's park space by 40%. The project stimulated retail and residential development along the loop, but has been criticized for its adverse effects on some Black communities. In 2013, the project received a federal grant of $18 million to develop the southwest corridor. In September 2019, the James M. Cox Foundation gave $6 million to the PATH Foundation which will connect the Silver Comet Trail to The Atlanta BeltLine, which was expected to be completed by 2022. Upon completion, the total combined interconnected trail distance around Atlanta for the Atlanta BeltLine and Silver Comet Trail will be the longest paved trail surface in the U.S., totaling about 300 miles (480 km).

Atlanta's cultural offerings expanded during the 2000s: the High Museum of Art doubled in size; the Alliance Theatre won a Tony Award; and art galleries were established on the once-industrial Westside. The College Football Hall of Fame relocated to Atlanta and the National Center for Civil and Human Rights museum was constructed. The city of Atlanta was the subject of a massive cyberattack which began in March 2018. In December 2019, Atlanta hosted the Miss Universe 2019 pageant competition. On June 16, 2022, Atlanta was selected as a host city for the 2026 FIFA World Cup.

Atlanta encompasses 134.0 square miles (347.1 km), of which 133.2 square miles (344.9 km) is land and 0.85 square miles (2.2 km) is water. The city is situated in the Deep South of the southeastern United States among the foothills of the Appalachian Mountains. At 1,050 feet (320 m) above mean sea level, Atlanta has the highest elevation among major cities east of the Mississippi River. Atlanta straddles the Eastern Continental Divide. Rainwater that falls on the south and east side of the divide flows into the Atlantic Ocean, while rainwater on the north and west side of the divide flows into the Gulf of Mexico. Atlanta developed on a ridge south of the Chattahoochee River, which is part of the ACF River Basin. The river borders the far northwestern edge of the city, and much of its natural habitat has been preserved, in part by the Chattahoochee River National Recreation Area.

Atlanta is 21 miles (34 km) southeast of Marietta, 27 miles (43 km) southwest of Alpharetta, 146 miles (235 km) southwest of Greenville, South Carolina, 147 miles (237 km) east of Birmingham, Alabama, and 245 miles (394 km) southwest of Charlotte, North Carolina.

Despite having lost significant tree canopy coverage between 1973 and 1999, Atlanta now has the densest urban tree coverage of any major city in the United States and is often called "City of Trees" or "The City in a Forest".

Atlanta is divided into 242 officially defined neighborhoods. The city contains three major high-rise districts, which form a north–south axis along Peachtree: Downtown, Midtown, and Buckhead. Surrounding these high-density districts are leafy, low-density neighborhoods, most of which are dominated by single-family homes.

Downtown contains the most office space in the metro area, much of it occupied by government entities. Downtown is home to the city's sporting venues and many of its tourist attractions. Midtown is the city's second-largest business district, containing the offices of many of the region's law firms. Midtown is known for its art institutions, cultural attractions, institutions of higher education, and dense form. Buckhead, the city's uptown district, is eight miles (13 km) north of Downtown and the city's third-largest business district. The district is marked by an urbanized core along Peachtree Road, surrounded by suburban single-family neighborhoods situated among woods and rolling hills.

Surrounding Atlanta's three high-rise districts are the city's low- and medium-density neighborhoods, where the craftsman bungalow single-family home is dominant. The eastside is marked by historic streetcar suburbs, built from the 1890s to the 1930s as havens for the upper middle class. These neighborhoods, many of which contain their own villages encircled by shaded, architecturally distinct residential streets, include the Victorian Inman Park, Bohemian East Atlanta, and eclectic Old Fourth Ward. On the westside and along the BeltLine on the eastside, former warehouses and factories have been converted into housing, retail space, and art galleries, transforming the once-industrial areas such as West Midtown into model neighborhoods for smart growth, historic rehabilitation, and infill construction.

In southwest Atlanta, neighborhoods closer to downtown originated as streetcar suburbs, including the historic West End, while those farther from downtown retain a postwar suburban layout. These include Collier Heights and Cascade Heights, historically home to most of the city's upper middle-class African-American population. Northwest Atlanta contains the areas of the city to west of Marietta Boulevard and to the north of Martin Luther King Jr. Drive, including those neighborhoods remote to downtown, such as Riverside, Bolton and Whittier Mill. The latter is one of Atlanta's designated Landmark Historical Neighborhoods. Vine City, though technically Northwest, adjoins the city's Downtown area and has recently been the target of community outreach programs and economic development initiatives.

Gentrification of the city's neighborhoods is one of the more controversial and transformative forces shaping contemporary Atlanta. The gentrification of Atlanta has its origins in the 1970s, after many of Atlanta's neighborhoods had declined and suffered the urban decay that affected other major American cities in the mid-20th century. When neighborhood opposition successfully prevented two freeways from being built through the city's east side in 1975, the area became the starting point for Atlanta's gentrification. After Atlanta was awarded the Olympic games in 1990, gentrification expanded into other parts of the city, stimulated by infrastructure improvements undertaken in preparation for the games. New development post-2000 has been aided by the Atlanta Housing Authority's eradication of the city's public housing. As noted above, it allowed development of these sites for mixed-income housing, requiring developers to reserve a considerable portion for affordable housing units. It has also provided for other former residents to be given vouchers to gain housing in other areas. Construction of the Beltline has stimulated new and related development along its path.

Most of Atlanta was burned in the final months of the American Civil War, depleting the city of a large stock of its historic architecture. Yet architecturally, the city had never been traditionally "southern": Atlanta originated as a railroad town rather than a southern seaport dominated by the planter class, such as Savannah or Charleston. Because of its later development, many of the city's landmarks share architectural characteristics with buildings in the Northeast or Midwest, as they were designed at a time of shared national architectural styles.

During the late 20th century, Atlanta embraced the global trend of modern architecture, especially for commercial and institutional structures. Examples include the State of Georgia Building built in 1966, and the Georgia-Pacific Tower in 1982. Many of the most notable examples from this period were designed by world renowned Atlanta architect John Portman. Most of the buildings that define the downtown skyline were designed by Portman during this period, including the Westin Peachtree Plaza and the Atlanta Marriott Marquis. In the latter half of the 1980s, Atlanta became one of the early homes of postmodern buildings that reintroduced classical elements to their designs. Many of Atlanta's tallest skyscrapers were built in this period and style, displaying tapering spires or otherwise ornamented crowns, such as One Atlantic Center (1987), 191 Peachtree Tower (1991), and the Four Seasons Hotel Atlanta (1992). Also completed during the era was the Bank of America Plaza built-in 1992. At 1,023 feet (312 m), it is the tallest building in the city and the 14th-tallest in the United States.

The city's embrace of modern architecture has often translated into an ambivalent approach toward historic preservation, leading to the destruction of many notable architectural landmarks. These include the Equitable Building (1892–1971), Terminal Station (1905–1972), and the Carnegie Library (1902–1977). In the mid-1970s, the Fox Theatre, now a cultural icon of the city, would have met the same fate if not for a grassroots effort to save it. More recently, preservationists may have made some inroads. For example, in 2016 activists convinced the Atlanta City Council not to demolish the Atlanta-Fulton Central Library, the last building designed by noted architect Marcel Breuer.

Under the Köppen classification, Atlanta has a humid subtropical climate (Cfa) with generous precipitation year-round, typical for the Upland South. The city is situated in USDA Plant Hardiness Zone 8a, with the northern and western suburbs, as well as part of Midtown transitioning to 7b. Summers are hot and humid, with temperatures somewhat moderated by the city's elevation. Winters are overall mild but variable, occasionally susceptible to snowstorms even if in small quantities on several occasions, unlike the central and southern portions of the state. Warm air from the Gulf of Mexico can bring spring-like highs while strong Arctic air masses can push lows into the teens °F (−7 to −12 °C).

July averages 80.9 °F (27.2 °C), with high temperatures reaching 90 °F (32 °C) on an average of 47 days per year, though 100 °F (38 °C) readings are not seen most years. January averages 44.8 °F (7.1 °C), with temperatures in the suburbs slightly cooler due largely to the urban heat island effect. Lows at or below freezing can be expected 36 nights annually, but the last occurrences of temperatures below 10 °F (−12 °C) were December 24, 2022, and January 2014, eight years apart. Extremes range from −9 °F (−23 °C) on February 13, 1899 to 106 °F (41 °C) on June 30, 2012. Average dewpoints in the summer range from 63.7 °F (17.6 °C) in June to 67.8 °F (19.9 °C) in July.

Typical of the southeastern U.S., Atlanta receives abundant rainfall that is evenly distributed throughout the year, though late spring and early fall are somewhat drier. The average annual precipitation is 50.43 in (1,281 mm), while snowfall is typically light and rare with a normal of 2.2 inches (5.6 cm) per winter. The heaviest single snowfall occurred on January 23, 1940, with around 10 inches (25 cm) of snow. However, ice storms usually cause more problems than snowfall does, the most severe occurring on January 7, 1973. Tornadoes are rare in the city itself, but the March 14, 2008, EF2 tornado damaged prominent structures in downtown Atlanta.

The 2020 United States census reported that Atlanta had a population of 498,715. The population density was 3,685.45 persons per square mile (1,422.95/km). The racial and ethnic makeup of Atlanta (including Hispanics) was 51.0% Black or African American, 40.9% non-Hispanic white, 4.2% Asian and 0.3% Native American, and 1.0% from other races. 2.4% of the population reported two or more races. Hispanics and Latinos of any race made up 6.0% of the city's population. The median income for a household in the city was $77,655 in 2022. The per capita income for the city was $60,778 in 2022. Approximately 17.7% percent of the population was living below the poverty line in 2022. Circa 2024, of the Atlanta residents, 391,711 of them lived in Fulton County and 28,292 of them lived in DeKalb County.

In the 1920s, the Black population began to grow in Southern metropolitan cities like Atlanta, Birmingham, Houston, and Memphis. Since the 1970s, Atlanta has been widely recognized as a hub of African American political activism, education, entrepreneurship, and culture—earning it the reputation of being a Black mecca. However, in the 1990s, Atlanta started to experience Black flight. African Americans have moved outside the city seeking a lower cost of living or better public schools. The African-American share of Atlanta's population has declined faster than that of any racial group. The city's share of Black residents shrank from 67% in 1990 to 47% in 2020. Blacks made up nine percent of new Atlanta residents between 2010 and 2020. At the same time, Atlanta is home to a sizable foreign-born Black population, notably from Eritrea, Ethiopia, Ghana, Somalia, Liberia, and Nigeria.

With many notable investments occurring in Atlanta initiated by the 1996 Summer Olympics, the non-Hispanic White population of Atlanta began to rebound after several decades of White flight to Atlanta's suburbs. Between 2000 and 2020, the proportion of Whites in the city had strong growth. In two decades, Atlanta's White population grew from 33% to 39% of the city's population. Whites made up the majority of new Atlanta residents between 2010 and 2020.

The Hispanic and Latino populations of metro Atlanta have grown significantly in recent years. The largest Hispanic ancestries in Atlanta are Mexican, Puerto Rican and Cuban. There is a growing population of Mexican ancestry throughout the region, with notable concentrations along the Buford Highway and I-85 corridor, and now extending into Gwinnett County. In 2013, Metro Atlanta had the 19th largest Hispanic population in the United States.

The Atlanta area also has a fast growing Asian American population. The largest groups of Asian origin are those of Indian, Vietnamese, Chinese, Korean, Filipino, Pakistani and Japanese descent. Pew Research Center ranks the Atlanta area among the top 10 U.S. metropolitan areas by Indian population in 2019.

Early immigrants in the Atlanta area were mostly Jews and Greeks. Since 2010, the Atlanta area has experienced notable immigration from India, China, South Korea, and Jamaica. Other notable source countries of immigrants are Vietnam, Eritrea, Nigeria, the Arabian gulf, Ukraine and Poland. Within a few decades, and in keeping with national trends, immigrants from England, Ireland, and German-speaking central Europe were no longer the majority of Atlanta's foreign-born population. The city's Italians included immigrants from northern Italy, many of whom had been in Atlanta since the 1890s; more recent arrivals from southern Italy; and Sephardic Jews from the Isle of Rhodes, which Italy had seized from Turkey in 1912. Europeans from Great Britain, Ireland and Germany settled in the city as early as the 1840s. Most of Atlanta's European population are from the United Kingdom and Germany. Bosnian refugees settled in Atlanta.

Vietnamese people, Cambodians, Ethiopians and Eritreans were the earliest refugees formally brought to the city.

Of the total population five years and older, 83.3% spoke only English at home, while 8.8% spoke Spanish, 3.9% another Indo-European language, and 2.8% an Asian language. Among them, 7.3% of Atlantans were born abroad (86th in the US). Atlanta's dialect has traditionally been a variation of Southern American English. The Chattahoochee River long formed a border between the Coastal Southern and Southern Appalachian dialects. Because of the development of corporate headquarters in the region, attracting migrants from other areas of the country, by 2003, Atlanta magazine concluded that Atlanta had become significantly "de-Southernized". A Southern accent was considered a handicap in some circumstances. In general, Southern accents are less prevalent among residents of the city and inner suburbs and among younger people; they are more common in the outer suburbs and among older people. At the same time, some residents of the city speak in Southern variations of African-American English.

Atlanta has a thriving and diverse lesbian, gay, bisexual, and transgender (LGBT) community. According to a survey by the Williams Institute, Atlanta ranked third among major American cities, behind San Francisco and slightly behind Seattle, with 12.8% of the city's total population identifying as LGB. The Midtown and Cheshire Bridge areas have historically been the epicenters of LGBT culture in Atlanta. Atlanta formed a reputation for being a place inclusive to LGBT people after former mayor Ivan Allen Jr. dubbed it "the city too busy to hate" in the 1960s (referring to racial relations). Atlanta has consistently scored 100% on the Human Rights Campaign's Municipal Equality Index that measures how inclusive a city's laws, policies and services are for LGBT people who live or work there.

Religion in Atlanta, while historically centered on Protestant Christianity, now encompasses many faiths, as a result of the city and metro area's increasingly international population. Some 63% of residents identified as some type of Protestant according to the Pew Research Center in 2014, but in recent decades the Roman Catholic Church has increased in numbers and influence because of new migrants to the region. Metro Atlanta also has numerous ethnic or national Christian congregations, including Korean and Indian churches. Per the Public Religion Research Institute in 2020, overall, 73% of the population identify with some tradition or denomination of Christianity; despite continuing religious diversification, historically African-American Protestant churches continue prevalence in the whole metropolitan area alongside historic Black Catholic churches. The larger non-Christian faiths according to both studies are Judaism, Islam, and Hinduism. Overall, there are over 1,000 places of worship within Atlanta.

Atlanta is governed by a mayor and the 15-member Atlanta City Council. The city council consists of one member from each of the city's 12 districts and three at-large members. The mayor may veto a bill passed by the council, but the council can override the veto with a two-thirds majority. The mayor of Atlanta is Andre Dickens, a Democrat elected on a nonpartisan ballot whose first term in office began on January 3, 2022. Every mayor elected since 1973 has been Black. In 2001, Shirley Franklin became the first woman to be elected mayor of Atlanta, and the first African-American woman to serve as mayor of a major Southern city. Atlanta city politics suffered from a notorious reputation for corruption during the 1990s administration of Mayor Bill Campbell, who was convicted by a federal jury in 2006 on three counts of tax evasion in connection with gambling winnings during trips he took with city contractors.

As the state capital, Atlanta is the site of most of Georgia's state government. The Georgia State Capitol building, located downtown, houses the offices of the governor, lieutenant governor and secretary of state, as well as the General Assembly. The Governor's Mansion is in a residential section of Buckhead. Atlanta serves as the regional hub for many arms of the federal bureaucracy, including the Federal Reserve Bank of Atlanta and the Centers for Disease Control and Prevention (CDC). The City of Atlanta annexed the CDC into its territory effective January 1, 2018. Atlanta also plays an important role in the federal judiciary system, containing the United States Court of Appeals for the Eleventh Circuit and the United States District Court for the Northern District of Georgia.

Historically, Atlanta has been a stronghold for the Democratic Party. Although municipal elections are officially nonpartisan, nearly all of the city's elected officials are registered Democrats. The city is split among 14 state house districts and four state senate districts, all held by Democrats. At the federal level, Atlanta is split between three congressional districts. Most of the city is in the 5th district, represented by Democrat Nikema Williams. Much of southern Atlanta is in the 13th district, represented by Democrat David Scott. A small portion in the north is in the 11th district, represented by Republican Barry Loudermilk.

The city is served by the Atlanta Police Department (APD), which numbers 2,000 officers and oversaw a 40% decrease in the city's crime rate between 2001 and 2009. In 2012, Forbes ranked Atlanta as the 6th most dangerous American city but by 2023 the city dropped out of its top 10. Despite some improvement in crime, street gangs have continued to plague the city since the 1980s. In 2022, there was a 200% increase in gang-related charges in the city. In 2023, Money Inc named Atlanta the third worst gang city in the U.S. Also in 2023, it was estimated that about 1,000 gangs in the Atlanta area were responsible for at least 70% of all crime including identity theft, credit card fraud, drug trafficking, and human trafficking. The Georgia Bureau of Investigation Gang Task Force in partnership with the APD is leading efforts in dismantling gang activity and arresting culprits.

The Atlanta Fire Rescue Department provides fire protection and first responder emergency medical services to the city from its 35 fire stations. In 2017, AFRD responded to over 100,000 calls for service over a coverage area of 135.7 square miles (351.5 square kilometers). The department also protects Hartsfield–Jackson with five fire stations on the property, serving over 1 million passengers from over 100 countries. The department protects over 3000 high-rise buildings, 23 miles (37 kilometers) of the rapid rail system, and 60 miles (97 kilometers) of interstate highway.

The Georgia National Guard is based in the city.

Emergency ambulance services are provided to city residents by hospital-based Grady EMS (Fulton County), and American Medical Response (DeKalb County).

Atlanta in January 2017 declared the city was a "welcoming city" and "will remain open and welcoming to all". Nonetheless, Atlanta does not consider itself to be a "sanctuary city". Atlanta Mayor Keisha Lance Bottoms said: "Our city does not support ICE. We don't have a relationship with the U.S. Marshal's Service. We closed our detention center to ICE detainees, and we would not pick up people on an immigration violation."

In 2025, Atlanta Public Safety Training Center opened, a $118 million training center for police and firefighters.

With more than 15 colleges and universities, including three law schools and two medical schools, Atlanta is considered one of the nation's largest hubs for higher education. Three universities have earned the highest classification of "R1: Doctoral Universities – Very high research activity".

The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a prominent public research university in Midtown. It offers highly ranked degree programs in engineering, design, industrial management, the sciences, business, and architecture.

Georgia State University is a major public research university based in Downtown Atlanta; it is the second largest in student population of the 26 public colleges and universities in the University System of Georgia and is a significant contributor to the revitalization of the city's central business district.

Atlanta is home to nationally renowned private colleges and universities, most notably Emory University, a leading liberal arts and research institution that operates Emory Healthcare, the largest health care system in Georgia. The City of Atlanta annexed Emory into its territory effective January 1, 2018.

The Atlanta University Center is also in the city; it is the oldest and largest contiguous consortium of historically black colleges in the nation, comprising Spelman College, Clark Atlanta University, Morehouse College, and Morehouse School of Medicine. Atlanta contains a campus of the Savannah College of Art and Design, a private art and design university that has proven to be a major factor in the recent growth of Atlanta's visual art community. Atlanta also boasts American Bar Association accredited law schools: Atlanta's John Marshall Law School, Emory University School of Law, and Georgia State University College of Law.

The University of Georgia's Terry College of Business operates a satellite campus in Atlanta's Buckhead district, a major financial center in the city. This location facilitates Executive and Professional MBA programs plus executive education offerings. The Buckhead campus also serves as a hub where Terry students, alumni, faculty, and staff can engage with the business community.

The Atlanta Regional Council of Higher Education (ARCHE) is dedicated to strengthening synergy among 19 public and private colleges and universities in the Atlanta region. Participating Atlanta region colleges and universities partner on joint-degree programs, cross-registration, library services, and cultural events.

Approximately 49,000 students are enrolled in 106 schools in Atlanta Public Schools (APS), some of which are operated as charter schools. Atlanta is served by many private schools including, without limitation, Atlanta Jewish Academy, Atlanta International School, The Westminster Schools, Pace Academy, The Lovett School, The Paideia School, Holy Innocents' Episcopal School and Roman Catholic parochial schools operated by the Archdiocese of Atlanta.

In 2018 the City of Atlanta annexed a portion of DeKalb County containing the Centers for Disease Control and Emory University; this portion will be zoned to the DeKalb County School District until 2024, when it will transition into APS. In 2017 the number of children living in the annexed territory who attended public schools was nine.