Dr. Gregory House’s closest friend in House M.D. is Dr. James Wilson.
Robert Sean Leonard portrays Wilson, an oncologist and the head of the hospital’s Department of Oncology. Wilson is one of the few people willing to challenge House directly, even while repeatedly helping him through personal, professional, and legal problems.
Their friendship is central to the series. House often hides concern behind insults and manipulation, whereas Wilson generally expresses loyalty more openly. Their contrasting personalities create both the show’s comedy and some of its most serious emotional storylines.
Viewers sometimes confuse Wilson with Dr. Eric Foreman, another important colleague. Foreman is a neurologist and member of House’s diagnostic teams, while Wilson is House’s longtime friend and neighbor. The character’s full name is James Evan Wilson, but the single surname “Wilson” is the canonical answer to this question.