Born in Adrigole, County Cork, O'Sullivan first excelled at Gaelic football in his youth. He arrived on the inter-county scene at the age of twenty when he first linked up with the Cork under-21 team. He made his senior debut during the 1968-69 league. O'Sullivan quickly became a regular member of the starting fifteen and won one All-Ireland medal and three Munster medals.
As a member of the Munster inter-provincial team for five consecutive years O'Sullivan won two Railway Cup medals. With divisional side Beara he is a one-time Munster medallist while he also won one championship medal. With Adrigole O'Sullivan won numerous championship medals in all grades.
Throughout his career O'Sullivan made 16 championship appearances. He retired from inter-county football following the conclusion of the 1975 championship.