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