John Christopher Reilly (born May 24, 1965) is an American actor. Debuting in Casualties of War in 1989, he is one of several actors whose careers were launched by Brian De Palma. To date, he has appeared in more than fifty film productions, including three separate films in 2002, each of which was nominated for the Academy Award for Best Picture. He was nominated for an Academy Award for Best Supporting Actor for his role in Chicago and a Grammy Award for the song "Walk Hard", which he wrote and performed in Walk Hard: The Dewey Cox Story.
Reilly, the fifth of six children, was born to an Irish American father and a Lithuanian mother and raised in Chicago, Illinois. He was raised as a Catholic and graduated from Brother Rice High School. On the set of the film Step Brothers, Reilly and co-star Richard Jenkins realized while discussing having lived in Chicago that, when Reilly was four, Jenkins had once worked for Reilly's father.
Reilly made his film debut in the Brian De Palma film Casualties of War (1989) as PFC Herbert Hatcher. Although the role of Hatcher was written as a small one, De Palma liked Reilly's performance so much that the role was significantly expanded. Also notable in his film work throughout the 1990s was his supporting role alongside Mark Wahlberg in Paul Thomas Anderson's 1997 film Boogie Nights, in which he played the pornographic film star Reed Rothchild.