In House M.D., what was the name of House's deceased colleague whose suicide haunted him?

In House M.D., House’s deceased colleague was named Lawrence Kutner.

Lawrence Kutner was a sports-medicine specialist who joined House’s diagnostic team during the fourth season. Kal Penn played the character. Kutner was energetic, inventive, and willing to experiment, making him a distinctive member of the team despite his relatively short time on the show.

Kutner dies by suicide in the season-five episode “Simple Explanation.” The event shocks House because Kutner had shown no obvious warning that House recognized. The unexplained nature of the death intensifies House’s frustration and guilt, and Kutner later appears as a hallucination in several episodes. These appearances reflect House’s psychological state rather than Kutner’s literal return.

The storyline also had an important production reason. Kal Penn left House M.D. to work in the Obama administration as an associate director in the White House Office of Public Engagement. Viewers sometimes confuse Kutner with Amber Volakis, another former team member whose death deeply affects House, but they are separate characters and storylines.