 O'Shea played 16 seasons in the CFL for the Hamilton Tiger-Cats and Toronto Argonauts from 1993 to 2008.He retired second all-time in career tackles with 1,154 and is one of only three players to record over 1,000 tackles.He won the CFL's Most Outstanding Canadian Award in 1999 after recording 84 tackles, 13 special teams tackles and three interceptions that year.