Peter was born in 1955 in New York to Tom (an advertising executive) and Mary (a bacteriologist), an Irish Catholic family.
He attended Byram Hills High School in Armonk New York, and then Tufts University, graduating in 1977, and while there sung with the Beelzebubs.
In 1995, Peter appeared in an Encores! version of the musical, Pal Joey with Patti LuPone.
His previous Broadway appearances include Grease, as Danny Zuko (1970s), A Doll's Life, as Otto (1982), The Corn is Green, as Morgan Evans (1983), The Real Thing, as Billy (1984-1985), Long Day's Journey into Night, as Edmund Tyrone (1986), Guys and Dolls, as Sky Masterson (early 1990s), Noises Off, as Lloyd Dallas (2001-2002) and Funny Girl, as Nick Arnstein (2002).
Peter was about to be named Brian Christopher Gallagher but his mother thought that his initials BCG were the initials of a bacillus.
Peter is a skilled golfer.
On April 5 2007, Peter Gallagher received the Light on the Hill Award at Tufts University. The award is given to notable alumni from Tufts who have demonstrated ambition, achievement, and active citizenship. Gallagher sang with the Beelzebubs and gave a speech to a full crowd in Cohen Auditorium.
Peter released his first album titled 7 Days in Memphis in November 2005.
Peter was the first of the cast of The O.C. to be cast. The scene that won him over was from the first episode, where Sandy helps Ryan tie a neck tie for the first time.
Peter attended the Best In Drag Show in Los Angeles which raised $150,000 for people with AIDS.
Peter hosts an annual award ceremony named "The Sandy Cohen Awards", or The Sandys, which, in honor of his The O.C. character, Sandy Cohen, awards a scholarship to a law school student at UC Berkeley who wants to become a public defender.
TV and Movie Awards
Golden Globe for Best Ensemble Cast for Short Cuts (1994) (Won).
Screen Actors Guild Award for Outstanding Performance by a Cast in a Theatrical Motion Picture for American Beauty (Won).
The Teen Choice Award for Choice TV Parental Units, with The O.C. co-star Kelly Rowan (2005) (nominated).
Peter was a TV commercial voice for Infiniti Q45 in 2000 and was featured in a 2003 commercial for Oxygen Network.
Was featured on the cover of Tiger Beat magazine for the December 1980 issue and the cover of TV Guide Magazine for the October 30, 2004 issue.
Was a considered for the role of Ethan in Supergirl, a 1984 movie.
Peter is 5 feet 9 inches (1.75 metres) tall, with blue eyes.
Nominated for a Tony Award for Long Day's Journey into Night for Best Featured Actor in 1986 and nominated for a Drama Desk Award for Guys and Dolls for Outstanding Actor in a Musical (1992).
A Theatre World Award for A Dolls Life (1982-1983 Season).
Lucille Lortel Award, Drama Desk Award for Unique Theatrical Experience, Outer Critics Circle Award for Outstanding Off-Broadway Play for The Exonerated (2003).
Peter Gallagher: (About what one of his fans said about his eyebrows) Somebody said, 'I'd like to cut them up, make tea out of them, and drink it.'
Peter Gallagher: Whether it's on top of a phone booth or a $200 million soundstage, it's about stories.
Peter Gallagher: When I was a child, nobody I knew of ever became an actor or entertainer, it was just not something that seemed possible for regular people.
Peter Gallagher: My kids do think The OC is a cool show. But my stature at home hasn't really been affected by what I do at work.
Peter Gallagher: My eyebrows make a more profound impact on other people than they do on me. I just let 'em grow.
Peter Gallagher: It never occurred to me that you might sing or act for a living. I was thinking about becoming a fireman or businessman like my dad.
Peter Gallagher: In an attempt to amuse my friends and family, I would do impressions of Dean Martin, singing Everybody Loves Somebody. I secretly really enjoyed singing the song.
Peter Gallagher: I was probably 11 by the time I saw a movie.
Peter Gallagher: I was about to get a degree in economics when I accepted that I'd be a lousy businessman, and if I didn't give acting a try I'd regret it for the rest of my life.
Peter Gallagher: I made my Broadway debut in the revival of Hair and followed it up with the bus and truck tour of Grease.
Peter Gallagher: Around 5th and 6th grade I thought Dean Martin was the coolest guy in the world; he was a great singer, had his own television show and acted in movies.