Who plays oncologist James Wilson in House M.D.?

Robert Sean Leonard plays oncologist James Wilson in House M.D.

Dr. James Wilson is Gregory House's closest friend and a recurring moral counterweight to House's cynicism. Wilson works in oncology at Princeton-Plainsboro Teaching Hospital, where his professional concern for patients contrasts with House's more confrontational approach to diagnosis and treatment.

The friendship between House and Wilson is one of the show's longest-running relationships. Wilson often challenges House's decisions, helps interpret his behavior, and still remains loyal despite repeated conflicts. Their bond also drives major storylines involving trust, responsibility, and personal sacrifice.

Robert Sean Leonard was already known for film and stage work before joining the series. He appeared in the film Dead Poets Society and earned a Tony Award for the Broadway production of The Invention of Love. The role of Wilson is sometimes confused with the roles of other members of House's diagnostic team, including Eric Foreman, played by Omar Epps.