Dr. Lawrence Kutner

Kutner is one of the new fellows House hires after gutting his original team, chosen partly for the sheer oddness of his application. He's an internist and diagnostician with an unflaggingly sunny disposition, eager to please, quick with off-kilter theories, and unbothered by the ethical corner-cutting House expects of his staff.

Kal Penn plays him as almost aggressively likable in a show built on misanthropy, which makes him a genuine tonal anomaly in House's world rather than just another sardonic doctor-in-training. His optimism reads as a real character trait, not naivety to be punished, and that sincerity is what makes him stand out among the rotating differential-diagnosis crew.