Although Knepper did not intend to work in film and television projects, he began his television and film career in 1986 with
The Paper Chase and ''
That's Life!. Knepper went on to have larger roles in such films as Wild Thing, Young Guns II, When the Bough Breaks and Everyone Says I Love You. He made appearances on such television series as The Twilight Zone, Star Trek: The Next Generation, ER and Law & Order. In 2005, after a recurring role on the HBO series Carnivàle, Knepper was cast in his best-known role, as Theodore "T-Bag" Bagwell in Prison Break. The series received positive reviews upon release, and "T-Bag" is often considered to be one of the greatest television villains of all time. During his time on Prison Break
, Knepper starred in a number of films; Good Night, and Good Luck, Hitman, Transporter 3 and The Day the Earth Stood Still''. After
Prison Break ended in 2009, Knepper was cast as villain
Samuel Sullivan in the fourth and final season of
Heroes. After this, he went on to have a recurring role in
Stargate Universe in 2010. He guest-starred on season six of
Criminal Minds as Rhett Walden, a serial killer. The same year he played the titular character in the film adaptation of
Burning Daylight. In addition, Knepper appeared as Honolulu Police Internal Affairs detective Rex Coughlin in two episodes of
Hawaii Five-0. In 2011, he reprised his role of T-Bag in one episode of the
A&E series
Breakout Kings. The next year, he played
Frank Sinatra in
My Way, a biopic of
Claude François, a French pop singer who wrote the song "
Comme d'habitude", the original version of Sinatra's song "
My Way". Knepper was cast in the 2013 television series
Cult as Roger Reeves, an actor playing Billy Grimm on a show called Cult. The show was canceled after only one season. The same year, he appeared in
R.I.P.D.,
Percy Jackson: Sea of Monsters and guest starred on the television series
The Blacklist (episode: "The Courier"). At the end of 2013, the
TNT series
Mob City premiered, in which Knepper played gangster Sid Rothman. In 2014, Knepper guest starred in episodes of
Arrow and
The Flash as master hacker and time-and-motion study expert
William Tockman / Clock King. Beginning in 2015, Knepper had a recurring role on
iZombie as Angus McDonough, the estranged and abusive father of Blaine DeBeers (
David Anders). It was announced in July 2017 that Knepper would be promoted to the show's main cast for season 4. Knepper was cast in the reboot of
David Lynch's
Twin Peaks as gangster Rodney Mitchum. He later voiced the audiobook adaptation for the tie-in epistolary novel of the show called
The Secret History of Twin Peaks. == Personal life ==