James Evan Wilson,M.D., is a fictional character on the Fox medical drama House. He is played by Robert Sean Leonard. The character first appears in the pilot when he introduces a medical case to Dr. Gregory House, the eponymous protagonist. Wilson is Dr. House's only true friend, and frequently provides him with consultations and aid. Wilson is the head of the Department of Oncology at Princeton-Plainsboro Teaching Hospital.

During the show's run, the characters of House and Wilson have been compared to Sherlock Holmes and Doctor Watson. Wilson's portrayer, Robert Sean Leonard, has stated that his character and Dr. House were originally supposed to play these roles; but Dr. House's diagnostic team has taken over Dr. Wilson's part. Leonard also read the script of the pilot episode of CBS' Numb3rs and was planning to audition. He auditioned for House instead because he felt he would more enjoy playing the character that House went to for help and because he liked The Odd Couple dynamic of the relationship.

James Wilson (1742–1798) was one of the Founding Fathers of the United States and a signer of the United States Declaration of Independence. Wilson was elected twice to the Continental Congress, and was a major force in drafting the United States Constitution. A leading legal theorist, he was one of the six original justices appointed by George Washington to the Supreme Court of the United States.

One of seven children, Wilson was born to a Presbyterian farming family on September 14, 1742 in Carskerdo, Fife, Scotland to William Wilson and Alison Landall. Wilson attended a number of Scottish universities without attaining a degree. Imbued with the ideas of the Scottish Enlightenment he moved to Philadelphia, Pennsylvania, in British America in 1766, carrying valuable letters of introduction. These helped Wilson to begin tutoring and then teaching at The Academy and College of Philadelphia (now the University of Pennsylvania). He petitioned there for a degree and was awarded an honorary Master of Arts several months later.

Robert Sean Leonard (born Robert Lawrence Leonard, February 28, 1969) is an American actor, who has regularly starred in Broadway and off-Broadway productions. Since 2004, he has played the role of Dr. James Wilson on the television series House, M.D.. He played Neil Perry in the 1989 movie Dead Poets Society.

Leonard was born in Westwood, New Jersey, the son of Joyce P. (née Peterson), a nurse, and Robert Howard Leonard, a Spanish teacher. He grew up in Ridgewood, where he attended Ridgewood High School before moving on to Fordham University and later Columbia University School of General Studies (GS). Because he shares his birth name with another actor, he uses the name of his brother Sean for his Screen Actors Guild membership.

Leonard is a three-time Tony Award nominee (1993, 2001 and 2003), winning in 2001 (Best Actor – Featured Play) for his role as A. E. Housman in Tom Stoppard's The Invention of Love. He had a prior association with Stoppard's work, creating the role of Valentine in the New York premiere of Arcadia at Lincoln Center in 1995. His 2003 Tony nomination was for his portrayal of Edmund Tyrone in a well-received revival of Eugene O'Neill's Long Day's Journey Into Night that co-starred Philip Seymour Hoffman and Brian Dennehy. Leonard has also appeared in Broadway musical productions, in 2001 replacing Craig Bierko as the lead performer in a successful revival of The Music Man. On February 8, 2011, it was announced that Leonard will co-star as Paul Verrall in the 2011 Broadway revival of Born Yesterday beginning in March.