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.
TV Shows(58)
Happy Face
D.A. Craig Calloway
2025
Happy's Place
Jim Jackoway
2024
Tracker
Buck Avery
2024
Fire Country
Harlan Denbo
2022
Echoes
Victor McCleary
2022
Outer Range
Judge Pettigrew
2022
Messiah
Cameron Collier
2020
The Romanoffs
Ron Hopkins
2018
Tom Clancy's Jack Ryan
Senator Mitchell Chapin
2018
The Resident
Joshua Williams
2018
S.W.A.T.
Carl Luca
2017
Shooter
Ray Brooks
2016
This Is Us
Arlo
2016
11.22.63
Arliss Price
2016
Manhattan
Psychiatrist
2014
Extant
Alan Sparks
2014
Rectify
Senator Roland Foulkes
2013
Bates Motel
Nick Ford
2013
Scandal
Lonnie Mencken
2012
Law & Order: LA
Jeb Monroe
2010
Rizzoli & Isles
Jonathan McKnight
2010
The Glades
Trent Staley
2010
FlashForward
CIA Director Keller
2009
NCIS: Los Angeles
Ret. U.S. Army General Richard Collins
2009
Leverage
Judge Roy
2008
The Mentalist
Sheriff Nelson
2008
Fringe
Sheriff Velchik
2008
Sons of Anarchy
Anthony Franklin
2008
Army Wives
Reverend Bankerd
2007
The Nine
Pete Burton
2006
The Unit
Ron Cheals
2006
Commander in Chief
Congressman Wilcox
2005
Ghost Whisperer
Nolan
2005
Criminal Minds
Det. Yarbough
2005
Close to Home
Don Wheeler
2005
Prison Break
Herb Stanton
2005
Grey's Anatomy
Gary Clark
2005
Numb3rs
Boyd Keene
2005
Boston Legal
Dr. Robert McLean
2004
LAX
Alonso Mathews
2004
NCIS
Riley McCallister
2003
Without a Trace
Thomas Shannon
2002
CSI: Miami
Jerry Blackburn
2002
24
Richard Walsh
2001
Crossing Jordan
Chris Benz
2001
Boston Public
Dr. Bernard Colbert
2000
Roswell
Philip Evans
1999
The West Wing
Ron Butterfield
1999
Ally McBeal
Dr. Colbert
1997
The Shining
Daniel Edwards (uncredited)
1997
The Practice
Judge Robert Temple
1997
Millennium
County Prosecutor Calvin Smith
1996
JAG
Commander Bradley
1995
ER
Col. Ken Kilner
1994
Chicago Hope
Bill Wyzinski
1994
One West Waikiki
1994
Diagnosis: Murder
Sheriff Buck O'Hara
1993
The X-Files
Patrol Captain Van Gelder
1993
Movies(42)
War of the Worlds
Secretary of Defense Walter Crystal
2025
Bride Hard
Frank
2025
Air
Joe Dean
2023
Cold Call
Christian
2021
The Stand at Paxton County
Dell Connelly
2020
Clemency
Chaplain David Kendricks
2019
Indivisible
Chaplain Rogers
2018
Danger One
Beckwith
2018
The Grim Sleeper
Detective Simms
2014
Dallas Buyers Club
Richard Barkley
2013
J. Edgar
Senator McKellar
2011
Green Zone
Colonel Bethel
2010
Flying Lessons
Chief Dobbs
2010
Nothing But the Truth
CIA Director
2008
A Quiet Little Marriage
Bruce
2008
Crazy
Ralph Christianson
2008
Transformers
Tom Banacheck
2007
Around the Bend
Cowboy
2004
American Crime
Sheriff Smyth
2004
Secondhand Lions
Ralph
2003
Seabiscuit
Mr. Pollard
2003
Dreamcatcher
Gen. Matheson
2003
Traffic
Lawyer Rodman
2000
The Legend of Bagger Vance
O.B. Keeler
2000
ATF
ATF Asst. Director Ben Walker
1999
The Mod Squad
Greene
1999
Dancer, Texas Pop. 81
Mr. Lusk
1998
Virtual Obsession
1998
Standoff
Cult Leader (Voice)
1998
The Sunchaser
Agent Moreland
1996
Bushwhacked
Jon Jordan
1995
Awake to Danger
Detective Brickman
1995
Beyond Betrayal
Ray Pasquerello
1994
Blind Justice
Spencer Heymen
1994
Victim of Love: The Shannon Mohr Story
Dick Britton
1993
For Their Own Good
Clark Thompson
1993
Lorenzo's Oil
School Psychologist
1992
Jennifer Eight
Serato
1992
The Gun in Betty Lou's Handbag
Jergens
1992
An Unremarkable Life
Michael
1989
Sea of Love
Raymond Brown
1989
Ghost Story
Churchill
1981