O'Neill first played Gaelic football to a high standard as a student at
St Patrick's Academy in
Dungannon. He was part of the first team to have success for the school when the Corn na nÓg title was claimed, while he also earned selection to the
Ulster Colleges team. He later studied at the
College of Technology in
Belfast but declined an offer from
Queen's University to line out with them in the
Sigerson Cup. By that stage O'Neill had begun his club career with
Coalisland Na Fianna. He won two Tyrone MFC medals in 1950 and 1952, before winning his sole
Tyrone SFC medal in 1955. O'Neill first appeared on the inter-county scene with
Tyrone as a member of the
minor team in 1951. It was the first of four successive years with the under-18 team before later lining out with the
junior team. O'Neill began his association with the
senior team in 1952. He was just 19 when he
captained Tyrone to their very first
Ulster SFC title in 1956. O'Neill won a second successive provincial title in 1957, as well as claiming
Dr McKenna Cup and
Dr Lagan Cup successes. He retired from inter-county activity in 1968 after serving as
player-manager for his last season with the team. O'Neill's inter-county performances earned his inclusion on the
Ulster inter-provincial team on 10 occasions. His five
Railway Cup wins came in 1960, 1963, 1964, 1965 and 1966. ==Management career==