In House M.D., which doctor is House's closest friend and an oncologist?

In House M.D., James Wilson is House's closest friend and Princeton-Plainsboro's oncologist.

Wilson is played by Robert Sean Leonard and serves as the head of the Department of Oncology. His work treating cancer patients contrasts with House's diagnostic investigations, but the two doctors repeatedly rely on one another when difficult cases become personal or ethically complicated.

Their friendship is one of the show's longest-running relationships. Wilson is more empathetic and socially conventional than House, yet he tolerates House's provocations and understands his reasoning better than most colleagues. House, in turn, often treats Wilson as his most trusted sounding board.

The character's full name is James Evan Wilson. The surname is sometimes confused with other recurring doctors in the series, but Wilson is the oncologist played by Leonard. His final major storyline centers on his terminal cancer diagnosis in the eighth season.