Born in Newberry, Michigan on July 15, 1952, Terry O'Quinn is a prolific American character actor. With a ready smile, highish voice, and Midwestern accent, he has tended to play a lot of Wolf In Sheeps Clothing characters. His best known role is cubicle slave turned jungle visionary John Locke on Lost, as well as the Man in Black posing as Locke. Other high-profile roles include the first two The Stepfather movies and The Rocketeer, as well as the TV series Alias, JAG, Millennium, Star Trek: The Next Generation, The X-Files, The West Wing and Hawaii Five-0.
- Production Posse: Between appearing in The X-Files, Millennium, The X-Files: Fight the Future and Harsh Realm he was known as "Mr. Ten Thirteen"
- Stage Name: Born Terry Quinn, he threw an 'O' in because there was another actor named Terry Quinn.
- Heaven's Gate (1980) as Captain Minardi
- Places in the Heart (1984) as Buddy Kelsey
- Silver Bullet (1985) as Sheriff Joe Haller
- The Stepfather (1987) and Stepfather II (1989) as the Stepfather
- The Rocketeer (1991) as Howard Hughes
- Son of the Morning Star (1991) as General Alfred Terry
- Tombstone (1993) as Mayor John Clum
- Ghosts of Mississippi (1996) as Judge Hillburn
- Primal Fear (1996) as Bud Yancy
- Millennium (TV Series) (1996-1999) as Peter Watts
- The X-Files: Fight the Future (1998) as Special Agent in Charge Darius Michaud
- Lost (TV Series) (2004-2010) as John Locke
- 666 Park Avenue (TV series) (2012) as Gavin Doran
- Phineas and Ferb (TV series) (2014) as Professor Mystery
- Castle Rock (TV series) (2018-present) as Dale Lacy
- FBI: Most Wanted (TV Series) (2019-) as Byron LaCroix
- Resident Alien (TV Series) (2021) as Peter Bach (special guest)