Pileggi began acting while he was a high school student in Turkey, playing musical theater. After returning to Austin from Iran, he performed in local theaters and continued his acting career with small roles in B-movies and guest roles in television series, such as
Dallas,
China Beach,
Code of Vengeance, and
Walker, Texas Ranger. In the 1980s, Pileggi starred in several films, including ''
Three O'Clock High, as Duke "The Duker" Herman, an overzealous tough-as-nails high school parking lot security guard. In 1988, he starred in "Brothers In Arms" as one of the villains (Caleb) and in Shocker as body-possessing serial killer Horace Pinker. The latter was directed by horror icon Wes Craven. Pileggi played the villain in the 1991 television film, Knight Rider 2000, a sequel to the original television series Knight Rider. He also appeared briefly in the 1992 film Basic Instinct as an investigating police officer in the interrogation scene of Michael Douglas. He also appeared in the 1995 vampire film Vampire in Brooklyn'' (also directed by Craven) as an Italian mobster. His most notable role was as the
FBI's Assistant Director
Walter Skinner on
The X-Files. The role was originally recurring, but the part expanded, and in 2001 he became a regular member of the cast. The character gradually became the most integral character besides the two leads. He remained with the series until its end in 2002. Pileggi played the character in the 1998
The X-Files film and in the 2008 film
The X-Files: I Want to Believe. He also reprised the role in the 2016 miniseries. Pileggi's later work has included starring in the short-lived series
Tarzan and co-starring with
Barbara Hershey and
Oliver Hudson in the short-lived series
The Mountain. He played the recurring role of character
Colonel Steven Caldwell, Commander of the Earth Battlecruiser,
Daedalus, in the second (2005) and subsequent seasons of the television series
Stargate Atlantis. He also appeared in an episode of
CSI: Crime Scene Investigation and in 2006 had a regular guest role on
Day Break as Robbery/Homicide Detective Spivak. Pileggi also appeared on the
Cold Case episode "Offender", as a father accused of molesting and murdering his own son, who then threatens to murder one child sex offender per day until the case is reopened and solved. Pileggi also played the role of Larry Jennings, chairman of the board of the hospital, in ''
Grey's Anatomy. In a first-season episode of That '70s Show'' he played Red Forman's swinger, navy buddy, Bull, alongside his real life wife, Arlene. Pileggi appeared in two episodes of
Law & Order: Special Victims Unit as
DEA agent Jack Hammond. Since 2008, Pileggi has played Ernest Darby, the head of a
white supremacist gang called the "Nordics", in the
FX drama
Sons of Anarchy . He also played
spree killer Norman Hill (AKA The Road Warrior) on a season four episode of
Criminal Minds, titled "Normal". Pileggi has also done some voice acting. His voice was featured as the
githzerai Dak'kon in the video game
Planescape: Torment. He voices
Commissioner James Gordon on the
Kids' WB series
The Batman. Pileggi also hosted the
Fox specials ''
Breaking the Magician's Code: Magic's Biggest Secrets Finally Revealed and Conspiracy Theory: Did We Land on the Moon?''. He also played the recurring role of Sam and Dean Winchester's maternal grandfather, Samuel Campbell, in the TV series
Supernatural. Pileggi starred in the
TNT drama series
Dallas as
Harris Ryland. He was promoted to series regular in the second season. As of 2014, Pileggi is on the advisory board of
Sci-Fest, the first annual Los Angeles Science Fiction One-Act Play Festival, held in May 2014. Since 2021, Pileggi has played Bonham Walker, the father of the titular Cordell Walker, in
The CW crime drama series
Walker reboot. ==Filmography==