John Christopher Reilly is an American actor. He is known as a character actor taking leading and supporting roles in independent drama films and studio comedies. He gained exposure through his supporting roles in Casualties of War (1989), Days of Thunder (1990), Hard Eight (1996), Boogie Nights (1997), Magnolia (1999), Gangs of New York (2002) and The Aviator (2004). Reilly was nominated for the Academy Award for Best Supporting Actor and the corresponding Golden Globe Award for his role in the musical film Chicago (2002). Reilly's other notable films include The River Wild (1994), The Thin Red Line (1998), and The Hours (2002).
Reilly gained prominence for his roles in comedy films such as Cal Naughton Jr. in Talladega Nights: The Ballad of Ricky Bobby (2006). He then went on to play the title character in Walk Hard: The Dewey Cox Story (2007), and Dale Doback, one of the two step brothers, in Step Brothers (2008). Meanwhile, Reilly began co-starring as Dr. Steve Brule in the comedic television series Tim and Eric Awesome Show, Great Job! (2007–2010), which led to the spin-off series Check It Out! with Dr. Steve Brule (2010–2016).