1973-77: Attended Tufts University. He sang in a group called the Beelzebubs, which is a "mini rock choir" (a capella group) at Tufts.
Was a considered for the role of Ethan in Supergirl (1984).
Was nominated for the 1986 Tony Award (New York City) for Supporting or Features Actor in a Drama for "Long Day's Journey into Night".
Son Jamey Gallagher (born in 1990) and daughter Kathryn Gallagher (born in 1993).
Sandy Cohen, Gallagher's character on "The O.C." (2003), was ranked #25 in TV Guide's list of the "50 Greatest TV Dads of All Time" [20 June 2004 issue].
2004: Attended the Best In Drag Show in Los Angeles which raised $150,000 for AIDS afflicted. The show's producer/director was Tom Perdoe.