After beginning his career with stage roles, including a part in the original Broadway production of Grease in the '70s, Gallagher segued into TV and film projects in the '80s, usually playing leads in television productions and supporting parts in films. His convincing turn as a cheating yuppie in the Steven Soderbergh film Sex, Lies, and Videotape led to roles in high-profile projects such as Robert Altman's The Player and Tim Robbins' Bob Roberts. His career chugged along at a respectable pace until a part as a California patriarch on the hit prime-time soap The O.C. kicked it into overdrive in 2003. After the show ended in 2007, he returned to the stage for a revival of The Country Girl, opposite Morgan Freeman and Frances McDormand. He continues to appear on stage and on both the big and small screens.
- Originally was to be named Brian Christopher Gallagher, but his mother (a bacteriologist) realized that BCG are the initials for a certain strain of bacillus and changed her mind.
- Sang in an a capella group called the Beelzebubs at Tufts University.
- Made his Broadway debut in the original production of Hair in 1977.
- Released his debut album, 7 Days in Memphis, in 2005 after signing a deal with Epic Records executives, who were impressed by his cover of "Don't Give Up On Me" in an episode of The O.C.
- 1999, Screen Actors Guild Awards — Outstanding Performance by a Cast in a Motion Picture: Winner
- 2015, Critics' Choice Television Awards — Best Guest Performer in a Comedy Series: Nominee
- 1986, Tony — Actor (Featured Role--Play): Nominee
- Mary Gallagher — Mother
- Paula Harwood — Wife
- Kathryn Gallagher — Daughter
- Tom Gallagher — Father
- Paula Harwood — Fiancée
- James Gallagher — Son
- Jamey Gallagher — Son
- Tufts University, Boston, Massachusetts, United States (BA in Economics, 1977); attended University of California, Berkeley, California, United States; attended New England Conservatory of Music, Boston, Massachusetts, United States