Andrew Demetriou's reign as AFL supremo will end after the 2014 season.
Mike Fitzpatrick, Chairman of the AFL Commission announced the decision at a press conference which began at 10am at AFL House.
Fitzpatrick said that Demetriou had been a "significant force in our competition" and had presided over "a period of extraordinary growth".
"In summary, Andrew has been one of the most influential CEO's in our history," Fitzpatrick said.
Demetriou's deputy, Gillon McLachlan, would be frontrunner to take over as CEO.
Demetriou's family is attendance.
Commentator Anthony Hudson says the timing of the announcement, less than two weeks before the start of the season, is "extraordinary". The season launch takes place in Adelaide on Wednesday night. However, as Jon Pierik reported in late January, many in the AFL industry expected 2014 would be Demetriou's last at the AFL.
Pierik reported: "Demetriou did not deny in August that he had been head-hunted by the Association of Tennis Professionals, which at the time was searching for an executive chairman and president. He said he had no intention of leaving but admitted: 'I get lots of approaches.'"
Demetriou has been AFL CEO since 2003, presiding over a period of prosperity for the league, as its revenue from TV deals went to unsurpassed heights. He has overseen the expansion of the competition to 18 teams, with the introduction of the Gold Coast Suns and the Greater Western Sydney Giants.
However, his handling of the Essendon supplements scandal over the past year has been heavily criticised. At the weekend, News Limited published the names of Essendon players who may be facing ASADA sanctions. Hudson said that Demetriou "would have liked this whole thing (Essendon) sorted out before he left".
Issues facing the league currently include the implementation of "equalisation" measures designed to assist financially challenged clubs, and negotiations for the league to buy Etihad Stadium.
Demetriou, 52, played 106 games for North Melbourne and Hawthorn between 1981 and 1988. He was CEO of the AFL Player's Association between 1998 and 2000 and is also an AFL Commissioner.