DOB: 5 April 1962
Debut: Round 1, 1982 against Sydney at SCG
Last MFC Game: Round 16, 1986 against Hawthorn at Waverley
From: Seymour/Assumption College
Number: 51 (1981 Reserves) 6 (1982-1986 seniors)
Honours:
Under 19s premiership player - 1981
Games: 53 (54 total)
Goals: 11
Career Statistics
| Wins | Draws | Losses | Winning % |
| 19 | 0 | 34 | 35.84 |
Recruited after winning Assumption's best and fairest award, O'Sullivan played Under 19s from 1980 but suffered shoulder problems during his career, and was forced to have a staple inserted during his rookie year.
O'Sullivan was part of the 1981 Under 19s premiership side and graduated to the senior side the next year. After a rookie year where he played every match and scored two Brownlow votes, the wingman/half-back had a terrible run with injuries beginning in Round 1, 1983 when his shoulder staple broke during match against Collingwood and he missed the rest of the season. He returned in 1984, but a broken jaw in Round 10 ended O'Sullivan's season.
A relatively injury free 1985 saw O'Sullivan play 18 games before being restricted to five again the next season. He signed with Essendon in mid-1987, playing his only senior match with them the next year before leaving the club after an injury hit stint. O'Sullivan coached Seymour in 1992.
| Year | Games | Goals | Brownlow |
| 1982 | 22 | 7 | 2 |
| 1983 | 1 | 0 | 0 |
| 1984 | 7 | 0 | 0 |
| 1985 | 18 | 4 | 0 |
| 1986 | 5 | 0 | 0 |
Lists
Essendon
Media
Inside Football - 25/09/1980
Age - 23/06/1983, 05/06/1984
Football Fan - 04/1984
Inside Football - 24/06/1987