Peter MacNicol is an American actor. He received a Theatre World Award for his 1981 Broadway debut in the play Crimes of the Heart. His film roles include Galen in Dragonslayer (1981), Stingo in Sophie's Choice (1982), Janosz Poha in Ghostbusters II (1989), camp counselor Gary Granger in Addams Family Values (1993), and David Langley in Bean (1997).

MacNicol was born in Dallas, Texas, on April 10, 1954. He attended the University of Dallas and the University of Minnesota, where he studied theater. After graduating, he moved to New York City to pursue an acting career. MacNicol made his Broadway debut in 1981 in the play Crimes of the Heart. He won a Theatre World Award for his performance. He went on to appear in a number of other Broadway productions, including The Real Thing (1984), The Crucible (1996), and The Pillowman (2005). MacNicol has also had a successful career in film and television. He has appeared in a number of films, including Sophie's Choice (1982), Ghostbusters II (1989), Addams Family Values (1993), and Bean (1997). He is best known for his role as the eccentric lawyer John Cage in the FOX comedy-drama Ally McBeal (1997–2002), for which he won a Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series in 2001. MacNicol has also appeared in a number of other television shows, including 24 (2001), Numbers (2005), and Veep (2012-2019). He is a versatile actor who has shown his range in a variety of roles. MacNicol is married to Martha Cumming, and they have two children. He is a member of the Actors' Equity Association and the Screen Actors Guild.