Rise to Fame
Playing Neil Perry in Dead Poets Society (1989), the boy who kills himself after his father refuses to let him act, should have made Robert Sean Leonard a movie star. It didn't, by his own design. He co-founded a New York theater company with Ethan Hawke in 1991, won a Tony in 2001 for Tom Stoppard's The Invention of Love, and became exactly the kind of actor Hollywood usually loses to the stage.
In the Spotlight
Eight seasons as Wilson on House (2004-2012) is probably why most people recognize him, which is an odd outcome for someone who spent the 1990s building a serious stage career. Wilson was House's only real friend, the moral center of a show built around a misanthrope. Since House ended, he's done what he's always done: chosen stage work over profile-building, picking up roles in The Gilded Age and theater productions on both sides of the Atlantic when it suits him.
Side Notes
He dropped out of Ridgewood High School at 17 to act and was in film within the year. He co-founded the Malaparte theater company in 1991 with Ethan Hawke, James Waterston, Steve Zahn, and Frank Whaley. His 2003 Tony nomination came for playing Edmund Tyrone in Long Day's Journey Into Night alongside Philip Seymour Hoffman, Brian Dennehy, and Vanessa Redgrave. That's an absurd amount of talent on one stage.