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|Full name||Pierce O'Leary|
|Date of birth||November 5, 1959|
|Place of birth||Dublin, Ireland|
|1978||→ Philadelphia Fury (loan)||14||(0)|
|1978–1980||Republic of Ireland U21||5||(0)|
|1979–1980||Republic of Ireland||7||(0)|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
O'Leary signed for Shamrock Rovers in 1977 under Johnny Giles and made his debut in October  and went on to win the FAI Cup in 1978. A week after the Cup Final he signed for Philadelphia Fury where he spent three months. In 1981 he signed for Vancouver Whitecaps before joining Celtic in November 1984.
O'Leary earned youth caps and 7 Republic of Ireland national football team caps while at Milltown, five Republic of Ireland national under-21 football team caps and made three appearances for Rovers in European competition.
The tall centre-half made his Celtic debut in a 2-1 Scottish Cup victory at Hamilton Accies on January 30, 1985. He came on as substitute in the 1985 Scottish Cup final as Celtic came from behind to defeat Dundee United 2-1. He then made enough appearances to claim a League Championship medal after Celtic pipped Hearts for the title on the final day of the 1985-86 season.
He was forced to retire in 1988 due to recurring pelvic trouble.
- Pierce is the only player to have played for and against Shamrock Rovers in European competition.
- He was part of the first team to play a European tie at Milltown.
- He partnered his brother David O'Leary three times for Ireland against Bulgaria and Northern Ireland in 1979 and Holland in 1980.
- O'Leary is the only player to be brought on as a substitute to replace his brother in an International game at Wembley.
- The Hoops by Paul Doolan and Robert Goggins (ISBN 0-7171-2121-6)