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Michael O'Neill

​From Wikipedia, the free encyclopedia. Michael O'Neill (born May 29, 1951) is an American actor. With a career stretching through three decades, he usually portrays senior law enforcement or military officers. He is perhaps best known for his role as Special agent Ron Butterfield, the head of President Josiah Bartlet's Secret Service detail, on The West Wing. He played CTU Administrative Director Richard Walsh in the first two episodes of 24. He played Sgt. Maj. Ron Cheals in the CBS action-drama series The Unit. He starred in the Season Six 2 part Finale of Grey's Anatomy as the broken widower who holds the hospital hostage with a 9mm while pursuing the doctors responsible for unplugging his wife. His most notable film performances occur in Seabiscuit, Secondhand Lions, Transformers, Dancer, Texas Pop 81, Traffic, Sea of Love, A Quiet Little Marriage, Nothing But the Truth, and Green Zone. O'Neill graduated from Auburn University in 1974. After attending Auburn he spent time under the tutelage of actor Will Geer and his daughter, Ellen, at Theatricum Botanicum in Los Angeles before moving to New York to pursue his career there.

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May 29, 1947 In Montgomery, Alabama, United States
Movie/TV Credits:
First Appeared:
In the movie Ghost Story 1981-12-18
Latest Project:
Movie Cold Call 2021-02-04
Known For
Poster of The Grim Sleeper
Poster of Green Zone
Poster of Dreamcatcher
Poster of Traffic
Movie Cold Call Christian 2021-02-04
Series Messiah Cameron Collier 2020-01-01
Movie The Stand at Paxton County Dell Connelly 2020-05-02
Movie Clemency Chaplain David Kendricks 2019-12-27
Series The Resident Joshua Williams 2018-01-21
Series Tom Clancy's Jack Ryan Senator Mitchell Chapin 2018-08-30
Movie Indivisible Chaplain Rogers 2018-10-26
Movie Danger One Beckwith 2018-09-14
Series S.W.A.T. Carl Luca 2017-11-02
Series 11.22.63 Mr. Price 2016-02-15
Series This Is Us Arlo 2016-09-20
Series Extant Alan Sparks 2014-07-09
Movie The Grim Sleeper Detective Simms 2014-03-15
Series Bates Motel Nick Ford 2013-03-18
Series Rectify Senator Roland Foulkes 2013-04-22
Movie Dallas Buyers Club Richard Barkley 2013-11-17
Series Scandal Lonnie Mencken 2012-04-05
Movie J. Edgar Senator McKellar 2011-11-09
Movie Green Zone Colonel Bethel 2010-03-11
Series The Glades Trent Staley 2010-07-11
Series Rizzoli & Isles Jonathan McKnight 2010-07-12
Series FlashForward CIA Director Keller 2009-09-24
Movie Crazy Ralph Christianson 2008-03-02
Series Fringe Unknown 2008-09-09
Series Leverage Judge Roy 2008-12-07
Movie A Quiet Little Marriage Bruce 2008-11-07
Series The Mentalist Sheriff Nelson 2008-09-23
Movie Transformers Tom Banacheck 2007-06-27
Series The Nine Pete Burton 2006-10-04
Series Grey's Anatomy Unknown 2005-03-27
Series Criminal Minds Det. Yarbough 2005-09-22
Series Prison Break Herb Stanton 2005-08-29
Movie American Crime Sheriff Smyth 2004-04-06
Movie Around the Bend Cowboy 2004-10-08
Movie Seabiscuit Mr. Pollard 2003-07-22
Movie Dreamcatcher General Matheson 2003-03-21
Movie Secondhand Lions Ralph 2003-09-19
Series Without a Trace Thomas Shannon 2002-09-26
Series Crossing Jordan Chris Benz 2001-09-24
Series 24 Richard Walsh 2001-11-06
Movie Traffic Lawyer Rodman 2000-03-23
Movie The Legend of Bagger Vance O.B. Keeler 2000-11-02
Movie ATF Asst. A.T.F. Director Ben Walker 1999-09-06
Movie The Mod Squad Greene 1999-03-26
Series The West Wing Unknown 1999-09-22
Series Roswell Philip Evans 1999-10-06
Movie Virtual Obsession 1998-02-01
Movie Dancer, Texas Pop. 81 Mr. Lusk 1998-05-01
Movie The Sunchaser Agent Moreland 1996-05-29
Series JAG Commander Bradley 1995-09-23
Series Chicago Hope Unknown 1994-09-18
Movie Beyond Betrayal Ray Pasquerello 1994-10-11
Movie For Their Own Good Clark Thompson 1993-04-05
Series The X-Files Unknown 1993-09-10
Movie Victim of Love: The Shannon Mohr Story Dick Britton 1993-11-09
Movie Jennifer Eight Serato 1992-11-06
Movie Lorenzo's Oil School Psychologist 1992-12-30
Movie An Unremarkable Life Michael 1989-10-12
Movie Sea of Love Raymond Brown 1989-09-15
Movie Ghost Story Churchill 1981-12-18