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This article relies largely or entirely upon a . single source (January 2008) Michael O'Neill is an American actor.
O'Neill grew up in
Montgomery, Alabama and graduated from Auburn University in 1974.  After attending Auburn, he spent time under the tutelage of actor Will Geer and one of Geer's daughters, the actress Ellen Geer, at Theatricum Botanicum in Los Angeles before moving to New York to pursue his career there.
With a career stretching through three decades, he usually portrays senior law enforcement or military officers.
[ He played ] citation needed Special Agent Ron Butterfield, the head of President Josiah Bartlet's Secret Service detail, on , and The West Wing CTU Administrative Director Richard Walsh in the first two episodes of . He played Sgt. Maj. Ron Cheals in CBS' action drama series 24 . He starred in the Season 6 two-part finale of The Unit 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 Grey's Anatomy , Seabiscuit , Secondhand Lions , Transformers , Dancer, Texas Pop. 81 , Traffic , Sea of Love , A Quiet Little Marriage , and Nothing but the Truth . Green Zone Filmography [edit ] Film [edit ] Television [edit ]
Year Title Role Episode 1990 H.E.L.P. Cabot Are You There, Alpha Centauri? 1992 L.A. Law My Friend Flicker 1994 Picket Fences Prosecutor Larry Adler System Down 1995 Days of our Lives Father Jansen 2 episodes One West Waikiki Manpower 1996 The Cape Keith Mason The Need to Know 1997 The Pretender Captain Harrigan The Better Part of Valor Millennium County Prosecutor Calvin Smith Covenant Orleans Luther's Temptation ( The Shining TV mini-series) Dr. Daniel Edwards 1 episode 1998 The X-Files The Patrol Captain Drive 1999 Roswell Phillip Evans The Morning After JAG Cmdr. Bradley Shakedown 1999–2006 The West Wing Secret Service Agent Ron Butterfield 16 episodes 2000 Chicago Hope Bill Wyzinski Everybody's Special at Chicago Hope 2001 NYPD Blue Capt. Chuck Dowling Peeping Tommy Diagnosis: Murder Sheriff Buck O'Hara No Good Deed 24 Richard Walsh 12:00 a.m.-1:00 a.m., 1:00 a.m.-2:00 a.m. 2001–2002 Boston Public Dr. Bernard Colbert Chapter Twenty-Four, Chapter Twenty-Seven, Chapter Twenty-Eight, Chapter Thirty-One 2002 Ally McBeal Dr. Colbert All of Me Without a Trace Thomas Shannon Silent Partner 2003 Presidio Med Breathless Carnivàle Sheiff Lyle Donovan Tipton 2004 The Practice Judge Robert Temple Police State Judging Amy D.A. Dave Sherman My Little Runaway Crossing Jordan Chris Benz Out of Sight LAX Alonso Mathews Unscheduled Arrivals 2005 Boston Legal Dr. Robert McLean It Girls and Beyond Cold Case Warren Cousins 2005 Revolution ER Col. Ken Kilner Here and There Commander in Chief Congressman Wilcox First Strike, First Scandal JAG Maj. Gen. Harold Rossing Fair Winds and Following Seas 2006 Close to Home Don Wheeler The Rapist Next Door 3 lbs James Wills Lost for Words 2006–2007 The Unit Ron Cheals First Responders, Dedication, SERE, Exposure, Off the Meter, Paradise Lost The Nine Pete Burton Pilot, Heroes Welcome, The Inside Man 2007 Lincoln Heights Captain Suspicion K-Ville Father Dennehy Critical Mass Criminal Minds Det. Yarbough About Face 2008 Women's Murder Club FBI Agent Ted Thorne Never Tell The Mentalist Sheriff Nelson Redwood Prison Break Herb Stanton Shut Down, Selfless My Own Worst Enemy Alexander DeSantos Love in All the Wrong Places Leverage Judge Roy The Bank Shot Job 2009 FlashForward CIA Director Mr. Keller Gimme Some Truth Ghost Whisperer Male Ghost Ghost Busted Army Wives Reverent Bankerd Family Readiness, Disengagement Sons of Anarchy Judge Franklin Fa Guan 2010 Numb3rs Boyd Keene Scratch Fringe Sheriff Velchik Johari Window Miami Medical Dr. Bruce Kaye 88 Seconds Grey's Anatomy Gary Clark Sympathy for Parents, How Insensitive, Sanctuary, Death and All His friends NCIS Former NCIS Special Agent Riley McCallister Enemies Foreign, Enemies Domestic 2012 Vegas Mayor Ted Bennett Pilot 2014 Extant Alvin Sparks References [edit ] External links [edit ]