With looks that speak "common man" and a keen ability to communicate his character's words and thoughts, O'Quinn became, in the 1980s and 90s, one of those actors whose face you immediately recognize, but whose name is left to trivia buffs. After sporadic employment in New York in such efforts as the NBC soap opera "The Doctors" and co-starring with Faye Dunaway in "Curse of the Aching Heart" on Broadway in 1982, he began to be cast in supporting roles in movies and TV. O'Quinn made his film debut in Michael Cimino's "Heaven's Gate" (1980). A large boost to his career came with Robert Benton's "Places in the Heart" (1984), in which he was Buddy, a good ol' boy cotton mill owner who is also a nasty Ku Klux Klan member. That same year, he appeared in Gillian Armstrong's "Mrs. Soffel". It took Joseph Ruben's low-budget "The Stepfather" (1987) to win O'Quinn notice. As the titular character, he delivers an intense, chilling portrait of a man who goes from cheerful and pleasant to menacing and deadly with ease. He went on to reprise the role in an unnecessary and inferior sequel "Stepfather 2" (1989). O'Quinn went on to deliver strong support in Christopher Cain's "Young Guns" (1988) as the lawyer who arranges for the youthful hired guns to search out a corrupt land owner (Jack Palance) and Joe Johnston's "The Rocketeer" (1991), in which he portrayed Howard Hughes. He was Moira Kelly's wealthy father in "The Cutting Edge" (1992), the town mayor in "Tombstone" (1993) and appeared as a state attorney with a grudge against the defense lawyer (Richard Gere) in Gregory Hoblit's "Primal Fear" (1996). The actor remained a familiar face in high-profile feature films (as well as several lower-profile efforts), appearing as a judge in Rob Reiner's "Ghosts of Mississippi" (1996), a key character in the ongoing alien conspiracy in "The X-Files" feature film (1998), in the misguided attempt to "Dawson's Creek"-ize the Western genre "American Outlaws" (2001) and the hit comedy "Old School" (2003). Since making his primetime TV debut in "Right to Kill?" (Abc 1985), a fact-based story of domestic violence directed by John Erman, O'Quinn has reteamed with the director several times: he was one of Aidan Quinn's doctors in "An Early Frost" (NBC, 1985), one of the first network films to deal with AIDS; he appeared as Bonnie Bedelia's husband in "When the Time Comes" (Abc 1987), which grappled with assisted suicide; and he played Tyne Daly's husband in the divorce drama "The Last to Go" (Abc 1991). In addition, O'Quinn was featured in "At Mother's Request" (CBS, 1987), Gregory Hoblit's "Roe vs. Wade" (NBC, 1989), with Holly Hunter and Amy Madigan, "Son of the Morning Star" (Abc 1991), the biopic of General George Armstrong Custer in which he played General Alfred Terry, and "Don't Talk to Strangers" (USA, 1994), in which he was an alcoholic whose former wife suspects him of kidnapping their son. He subsequently appeared with Chris Cooperand David Schwimmer in the HBO plastic surgery drama "Breast Men" (1997) and opposite Gene Wilder in the comedy mystery "Murder in a Small Town" (1999). O'Quinn became an increasingly regular fixture on series television beginning in the late 1990s. In 1995 he had a recurring role on the short-lived sci-fi series "Earth 2" and was also cast as Capt. Thomas Boone on the pilot episode of the popular military drama "JAG," returning to the role frequently in subsequent seasons. After using him as different characters on episodes of "The X-Files," series creator Chris Carter cast O'Quinn in his short-lived sci-fi drama "Harsh Realm" as a renegade genra; controlling a virtual reality world. In 2003 O'Quinn began the first of many appearances on the J.J. Abrams-created spy series "Alias" as F.B.I. Asst. Director Kendall, while simultaneously recurring as General Nicholas Alexander on the NBC White House drama "The West Wing." His connection to Abrams would pay off handsomely when he was cast as the mysterious Locke on Abrams's clever adventure drama "Lost" (Abc 2004- ), the most enigmatic of the 48 plane crash survisors stranded on a seemingly deserted island.