Campion played his club football in Australia for Gold Coast Seagulls, St. George Dragons, Adelaide Rams, Brisbane Broncos, New Zealand Warriors and North Queensland Cowboys.
He would make his representative début for Queensland during the 1997 Super League Tri-series that year but sensationally was told by Rams coach Rod Reddy that he was not part of his plans for the club in 1998.
After leaving Adelaide, Kevin Campion was snapped up by Brisbane Broncos coach Wayne Bennett, and went on to play 80 games for the club between 1998 and 2000, including the 1998 and 2000 NRL Grand Finals.
Campion then signed with the New Zealand Warriors in 2001 and went on to play at lock forward in their 2002 NRL Grand Final loss to the Sydney Roosters.
Campion also represented Queensland on six occasions: four times in the annual State of Origin series, and twice in the Super League Tri-series.