Mares made his first grade debut for Parramatta in 1982 but only featured in three matches that season and was not a member of the 1982 premiership winning side.
In 1983, Mares was part of the Parramatta side which won its third consecutive premiership defeating Manly-Warringah in the grand final.
Over the next couple of seasons, Mares struggled with injuries and missed out on being selected in Parramatta's 1986 premiership winning team.
In 1989, Mares moved to Eastern Suburbs but only managed to make six appearances before a recurring knee injury forced him into retirement.
[2][3] In 2021, Mares pled guilty in Cooma local Court to not providing a sample to an oral test for drugs, driving a vehicle with menace, not obeying a police direction and not keeping to the left of a road.