Originally from Sydney in New South Wales, Hayes was recruited from the Pennant Hills Demons AFC by St.Kilda in the 1998 AFL Draft. Hayes was captain for the 2004 season as part of St Kilda's then policy of rotating the captaincy to a different player each season.
His honours include All-Australian selection in 2003, the same year that he also took out the Trevor Barker Award for the Saints' Best and Fairest player. He also won All-Australian selection in 2005 as one of the senior members of the Saints' midfield.
After a strong start to the 2006 season, Hayes ruptured his anterior cruciate ligament against the Kangaroos in round 9, requiring a minor knee reconstruction which sidelined him until the 2007 season. In just his fifth game back in the 2007 season he suffered a broken collarbone, sidelining him for three weeks, although he managed to come back and play 19 games for the year.
Hayes was a co-captain and part of the Saints' 2007 leadership group - dubbed the "Young Saints", which also included Justin Koschitzke, Luke Ball (co-captain) and Nick Reiwoldt (co-captain). Also included in the leadership group were Aaron Hamill, Fraser Gehrig, Nick Dal Santo and Robert Harvey.
In 2009 Hayes played his 200th AFL game in Round 9 against the Brisbane Lions at Etihad Stadium, during the match he amassed 31 possessions ensuring the Saints a 16 point victory.
