Namesakes
Fictional Characters from Television:
3 characters
Russ Brennan 2005 Bones 
Max Keenan (a.k.a. Brennan) 2005 Bones
Temperance "Bones" Brennan 2005 Bones
Hall-of-Famers:
1 basketball
(basketball) Joseph Brennan 1974
Notable Actors and Entertainers:
4 actors
Walter Brennan 1894-1974
Eileen Brennan 1932-2013
Bríd Brennan 1955-
Melissa Reeves (a.k.a. Brennan) 1967-
Notable Musicians:
2 singers
Moya Brennan 1952-
Enya (a.k.a. Brennan) 1961-
Oscar Award Winners:
1 actor
(actor) Walter Brennan 1937; 1939; 1941 Come and Get It; Kentucky; The Westerner