James Evan Wilson, M.D., is a fictional character on the Fox medical drama House. He is played by Robert Sean Leonard. The character is introduced in "Pilot" when he introduces a medical case to Gregory House, the protagonist of the show. He is House’s only true friend, and frequently provides House with consultations and aid. Wilson is the head of the Department of Oncology at Princeton-Plainsboro Teaching Hospital.
 
Wilson, one of three brothers from a Jewish household, has an undergraduate degree from McGill University, and higher degrees from Columbia and the University of Pennsylvania. Wilson has a history of failed marriages: his third marriage takes place during the show’s first season and, with the discovery of his wife’s infidelity, ends during the second.After the failure of his third marriage, Wilson lives in various temporary accommodations (including a stint at House’s own apartment) until he meets Amber. It is revealed in season 1 episode "Histories" that one of his brothers is homeless and that Wilson isn’t aware if he’s alive or dead as he hasn’t seen him in nine years.