Ian Lithgow was born in Cambridge, Massachusetts, eldest son of the actor John Lithgow and his first wife, Jean Taynton. He has two half siblings, Phoebe (born 1982) and Nathan (born 1983). He received his undergraduate degree from Harvard University and his M.A. in Clinical Psychology from Antioch University Los Angeles. He currently runs a practice in Lower Manhattan specializing in marriage and family therapy.
Lithgow is an award-winning actor who has performed in TV, film, and in regional theatres across the country, including the Goodman Theatre, the American Repertory Theatre, the Williamstown Theatre Festival, the Ahmanson Theatre, and the Pasadena Playhouse. Lithgow is best known for appearing in the 1990's NBC sitcom 3rd Rock from the Sun, playing the recurring role of Leon, a purportedly dim-witted student who attends the physics class of Dick Solomon (portrayed by real-life father John Lithgow). He created the role of Tony in Boy Gets Girl, which he performed at the Manhattan Theatre Club.
