James Wilson is Gregory House’s closest friend and the head of oncology in House M.D.
Wilson is played by Robert Sean Leonard and serves as one of the show’s principal emotional counterweights to House. Whereas House typically approaches people through skepticism and provocation, Wilson is often more empathetic and concerned with the personal consequences of medical decisions. Their friendship remains important even when House’s behavior causes serious problems.
Wilson’s specialty is medical oncology, the treatment of cancer. This role also places him close to patients facing life-changing diagnoses, giving the series a recurring way to explore questions about hope, honesty, and quality of life.
The friendship is sometimes confused with a professional partnership: Wilson does not lead House’s diagnostic team. House leads Diagnostic Medicine, while Wilson runs Oncology. Their different departments and personalities are central to the hospital’s social structure and to many of the show’s continuing storylines.