He played with his local club John Mitchel and was a member of the Down senior inter-county team from the 1950s until the 1960s.
O'Neill scored 85 goals and over 500 points for Down senior football team in his career, and was a key figure in the county’s All-Ireland victories of 1960, 1961 and 1968.
[1][2] Other honours include a Sigerson Cup medal with the Queen's University of Belfast in 1958, whom he later coached to further wins.
Along with Joe Lennon, Dan McCartan and Paddy Doherty, he was one of four Down men who won all three All-Ireland medals in the 1960s.
[citation needed] In 1984, the Gaelic Athletic Association centenary year, he was honoured by being named on their Football Team of the Century.