AC Ajaccio

Depending on sources, it is agreed that Ajaccio began playing in 1909–10. Their adopted colors are red and white stripes. Though they used to play in what was previously utilised as a sand dump, they decided to move to another, cleaner, safer stadium upon the insistence of Jean Lluis, father-in-law of club president Louis Baretti. The new stadium that was chosen held 5,000 spectators and was in use until 1969.

AC Ajaccio were elected Corsican champions on eight occasions, in 1920, 1921, 1934, 1939, 1948, 1950, 1955 and 1964, and are one of three big "island" teams, along with Gazélec Ajaccio and Bastia, the competition between the three being kept no secret. Spectators during the 1946 Corsican Cup final, held between A.C.A. and Sporting Bastia, were handed umbrellas to shield themselves from the violence. Upon refusal of a penalty which would have been awarded to ACA, violence erupted between the fans, who used umbrellas both to cause and shield themselves from violence. This final was abandoned and replayed much later.

A.C.A. became a professional team in 1965 thanks to the ambitious efforts of the club's leaders. They initially adopted the symbol of the polar bear, but this has since been dropped in favour of a more stylised logo that uses a part of the Corsican flag. They brought back the polar bear in 2014.

In 1967, the team became the first Corsican club to play in France's top division. Prior to the 2022–23 season, they were most recently in Ligue 1 in the 2013–14 season, when they were relegated after finishing in last place, following a spell of three seasons in the top flight; the drop was confirmed with defeat at neighbours Bastia.

In November 2014, Olivier Pantaloni returned for a third spell as manager. His team came third in 2017–18, qualifying for the play-offs, where they beat Le Havre in a semi-final marred by violence on and off the pitch, before losing the final to Toulouse. The club were denied promotion in 2019–20 when the season was curtailed with ten games remaining due to the coronavirus pandemic; Ajaccio were one point off the top two, who were the only ones to go up as the play-offs could not be contested. In the 2021–22 Ligue 2 season, Ajaccio were promoted back to Ligue 1 after finishing second. However, with three games in hand, the club were relegated directly back down.

On 27 June 2024, Ajaccio was administratively relegated to the Championnat National by the Direction Nationale du Contrôle de Gestion (DNCG) due to financial issues. They appealed the decision, and on the 11th of July 2024, they were reinstated in Ligue 2 for the 2024–25 season. On 24 June 2025, the club was once again provisionally relegated to the Championnat National. On 16 July 2025, relegation administratively is confirmed due to US Boulogne promoted to Ligue 2. On 14 August 2025, due to continuing financial issues, Ajaccio was excluded from any national-level competitions for 2025–26 season altogether.