Michael O'Neill
Acting
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.
Known for
Acting101
movieWar of the Worlds
2025
Secretary of Defense Walter Crystal
movieBride Hard
2025
Frank
tvHappy Face
2025
D.A. Craig Calloway
tvHappy's Place
2024
Jim Jackoway
tvTracker
2024
Buck Avery
movieAir
2023
Joe Dean
tvFire Country
2022
Harlan Denbo
tvEchoes
2022
Victor McCleary
tvOuter Range
2022
Judge Pettigrew
movieCold Call
2021
Christian
movieThe Stand at Paxton County
2020
Dell Connelly
tvMessiah
2020
Cameron Collier
movieClemency
2019
Chaplain David Kendricks
movieIndivisible
2018
Chaplain Rogers
tvThe Romanoffs
2018
Ron Hopkins
movieDanger One
2018
Beckwith
tvTom Clancy's Jack Ryan
2018
Senator Mitchell Chapin
tvThe Resident
2018
Joshua Williams
tvS.W.A.T.
2017
Carl Luca
tvShooter
2016
Ray Brooks
tvThis Is Us
2016
Arlo
tv11.22.63
2016
Arliss Price
tvManhattan
2014
Psychiatrist
tvExtant
2014
Alan Sparks
movieThe Grim Sleeper
2014
Detective Simms
movieDallas Buyers Club
2013
Richard Barkley
tvRectify
2013
Senator Roland Foulkes
tvBates Motel
2013
Nick Ford
tvVegas
2012
Mayor Ted Bennett
tvScandal
2012
Lonnie Mencken
movieJ. Edgar
2011
Senator McKellar
tvLaw & Order: LA
2010
Jeb Monroe
tvRizzoli & Isles
2010
Jonathan McKnight
tvThe Glades
2010
Trent Staley
movieGreen Zone
2010
Colonel Bethel
movieFlying Lessons
2010
Chief Dobbs
tvFlashForward
2009
CIA Director Keller
tvNCIS: Los Angeles
2009
Ret. U.S. Army General Richard Collins
movieNothing but the Truth
2008
CIA Director
tvLeverage
2008
Judge Roy
tvThe Mentalist
2008
Sheriff Nelson
tvFringe
2008
Sheriff Velchik
tvSons of Anarchy
2008
Anthony Franklin
movieCrazy
2008
Ralph Christianson
movieTransformers
2007
Tom Banacheck
tvArmy Wives
2007
Reverend Bankerd
tvThe Nine
2006
Pete Burton
tvThe Unit
2006
Ron Cheals
tvCommander in Chief
2005
Congressman Wilcox
tvCriminal Minds
2005
Det. Yarbough
tvClose to Home
2005
Don Wheeler
tvPrison Break
2005
Herb Stanton
tvGrey's Anatomy
2005
Gary Clark
tvNumb3rs
2005
Boyd Keene
movieAround the Bend
2004
Cowboy
tvBoston Legal
2004
Dr. Robert McLean
tvLAX
2004
Alonso Mathews
movieAmerican Crime
2004
Sheriff Smyth
tvNCIS
2003
Riley McCallister
movieSeabiscuit
2003
Mr. Pollard
movieDreamcatcher
2003
Gen. Matheson
tvWithout a Trace
2002
Thomas Shannon
tvCSI: Miami
2002
Jerry Blackburn
tv24
2001
Richard Welsh / Richard Walsh
tvCrossing Jordan
2001
Chris Benz
movieTraffic
2000
Lawyer Rodman
movieThe Legend of Bagger Vance
2000
O.B. Keeler
tvBoston Public
2000
Dr. Bernard Colbert
tvRoswell
1999
Philip Evans
tvThe West Wing
1999
Ron Butterfield
movieATF
1999
ATF Asst. Director Ben Walker
movieThe Mod Squad
1999
Greene
movieDancer, Texas Pop. 81
1998
Mr. Lusk
movieStandoff
1998
Cult Leader (Voice)
tvAlly McBeal
1997
Dr. Colbert
tvThe Shining
1997
Daniel Edwards (uncredited)
tvThe Practice
1997
Judge Robert Temple
tvMillennium
1996
County Prosecutor Calvin Smith
movieThe Sunchaser
1996
Agent Moreland
tvJAG
1995
Commander Bradley
movieBushwhacked
1995
Jon Jordan
movieAwake to Danger
1995
Detective Brickman
movieBeyond Betrayal
1994
Ray Pasquerello
tvER
1994
Col. Ken Kilner
tvChicago Hope
1994
Bill Wyzinski
movieBlind Justice
1994
Spencer Heymen
movieVictim of Love: The Shannon Mohr Story
1993
Dick Britton
tvDiagnosis: Murder
1993
Sheriff Buck O'Hara
tvThe X-Files
1993
Patrol Captain Van Gelder
movieFor Their Own Good
1993
Clark Thompson
movieLorenzo's Oil
1992
School Psychologist
movieJennifer Eight
1992
Serato
movieSea of Love
1989
Raymond Brown
movieGhost Story
1981
Churchill
Production2
movieThe Emperor's Club
2002
Co-Producer