Garret Dillahunt grew up in the state of Washington and attended the University of Washington where he studied journalism. He received his MFA from New York University's Graduate Acting Program.
He appeared on and off Broadway and in theaters around the country before he began pursuing film and television roles. He has two brothers: Brett, a teacher; and Eric, deceased.
- The Gifted
- The Mindy Project
- Hand of God
- 12 years a Slave
- The Last House on the Left (2009 Remake)
- No Country for Old Men
- Raising Hope
- Terminator: The Sarah Connor Chronicles
- John from Cincinnati
- One Life to Live
- Burn Notice
- Army of the Dead
- Brooklyn Nine-Nine
- He auditioned for the role of Negan on The Walking Dead but did not get the part.
- He previously appeared on Deadwood along with fellow Fear actors Kim Dickens, Dayton Callie, Ray McKinnon, and Keith Carradine.
- In the series, Garret Dillahunt portrayed Jack McCall, who killed a character named Wild Bill Hickok. The character of Wild Bill Hickok was portrayed by Keith Carradine.
- As of 2016, has appeared in three films that were nominated for the Best Picture Oscar: No Country for Old Men (2007), Winter's Bone (2010) and 12 Years a Slave (2013). Of those, No Country for Old Men (2007) and 12 Years a Slave (2013) are winners in the category.
- Keith's daughter, Martha Plimpton portrayed Virginia Slims Chance, the wife of Garret Dillahunt's character, Jebbidiah "Burt" Chance in Raising Hope.