Born Oct. 8, 1970, in Cambridge, Mass., Damon befriended neighbor Affleck in 1981. After making his feature debut (with one line) in 1988's Mystic Pizza, Damon performed with the American Repertory Theatre in Cambridge and various Harvard theater groups.
By the early 1990s, Damon began to focus on his film career, which soon was soaring. His notable movies include The Rainmaker (his first starring role, in 1997); Saving Private Ryan (1998, playing the titular soldier); The Talented Mr. Ripley (1999); and Ocean's Eleven (2001). A double Golden Globe nominee in 2009, Damon received nods for his lead role in The Informant and his supporting turn in Invictus, for which he also copped an Oscar nomination.