Namesakes
Notable Actors and Actresses:
4 actors, 1 comedian
Edmond O'Brien 1915-1985 
Conan O'Brien 1963-
Kieran O'Brien 1973-
Austin O'Brien 1981-
Dylan O'Brien 1991-
Notable Athletes:
1 cricket, 1 football, 1 rugby
(cricket) Niall O'Brien 1981-
(rugby) Seán O'Brien 1987-
(football) Kitt O'Brien 1990-
Notable Hosts and Presenters:
1 television
(television) Conan O'Brien 1963-
Notable Musicians:
1 musician/singer
Snow (a.k.a. O'Brien) 1969- reggae
Olympic Medalists:
2 gold, 1 gold/bronze, 1 gold/silver, 1 silver
(silver) Edward O'Brien 1936 4x400 m relay
(gold/silver) Parry O'Brien 1952; 1956; 1960 shot put
(gold/bronze) Ian O'Brien 1964 swimming - 200 m breaststroke; swimming - 4x100 m medley relay
(gold) Michael O'Brien 1984 swimming - 1500 m freestyle
(gold) Dan O'Brien 1996 decathlon
Oscar Award Winners:
1 actor
(actor) Edmond O'Brien 1954 The Barefoot Contessa
Pulitzer Award Winners:
1 winner
Tim O'Brien 1991 The Things They Carried
Saints:
1 blessed
Blessed Terence Albert O'Brien 1600-1651
Title Characters:
1 book
(book) Glory O'Brien 2012 Glory O'Brien's History of the Future