He was born in Dublin and died in Ormskirk, England. At the time of his death he was living in Marians Drive, Ormskirk, Lancashire.
A goalkeeper, Jimmy O'Neill joined Everton from junior football in Ireland in 1949. He made his début, against Middlesbrough, in August 1950. O'Neill played in the 1953 FA Cup semi-final and shared the goalkeeping duties with Harry Leyland during the promotion campaign of 1953-54. He went on to play a total of 213 games for Everton.
He also won 17 caps for the Republic of Ireland, making his début in a 6-0 defeat at the hands of Spain on 1 June 1952 in Madrid. O'Neill joined Stoke City for £5,000 in July 1960 and later had spells at Darlington and Port Vale.
Following his retirement from football, in his mid-30s, he ran a taxi firm in Ormskirk.