Delort re-joined his original club, AC Ajaccio, in June 2010. He scored his first two goals at professional level on 15 September 2010 against Le Havre in the French League Cup, before achieving his first goals in the Coupe de France on 12 November 2010. His first Ligue 2 goals contributed to victories against Angers on 17 December 2010 and against Istres. He signed his first professional contract for three and a half years with AC Ajaccio on 28 January 2011. On 11 March 2011, he was one of the players involved in a mass brawl when he was replaced in the match against Nantes. As a result of the incident, several players were given suspensions; both Delort and his teammate Carl Medjani received four-match bans. He earned promotion to Ligue 1 with AC Ajaccio during the 2010–11 season, after finishing 2nd in the league.
