He turned professional in 1970 and played on the European Tour until 1989. His first title came at the Greater Manchester Open in 1976, with his second victory coming at his national open in 1982. In 1975, O'Leary was selected for the Great Britain and Ireland Ryder Cup team, but lost all four of his matches.
European Tour wins (2)
Other wins (2)
1975 Holiday Inns Championship (South Africa), Sumrie-Bournemouth Better-Ball (with Jack Newton).