Michael O'Neill
Acting • Born 1947-05-29
Biography
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
100 credits
Transformers
Movie • 2007
Tom Banacheck
Green Zone
Movie • 2010
Colonel Bethel
Dreamcatcher
Movie • 2003
Gen. Matheson
The Gun in Betty Lou's Handbag
Movie • 1992
Jergens
Air
Movie • 2023
Joe Dean
Around the Bend
Movie • 2004
Cowboy
Blind Justice
Movie • 1994
Spencer Heymen
A Quiet Little Marriage
Movie • 2008
Bruce
Dancer, Texas Pop. 81
Movie • 1998
Mr. Lusk
War of the Worlds
Movie • 2025
Secretary of Defense Walter Crystal
Dallas Buyers Club
Movie • 2013
Richard Barkley
For Their Own Good
Movie • 1993
Clark Thompson
An Unremarkable Life
Movie • 1989
Michael
Bride Hard
Movie • 2025
Frank
Bushwhacked
Movie • 1995
Jon Jordan
The Grim Sleeper
Movie • 2014
Detective Simms
Virtual Obsession
Movie • 1998
The Legend of Bagger Vance
Movie • 2000
O.B. Keeler
Traffic
Movie • 2000
Lawyer Rodman
Nothing But the Truth
Movie • 2008
CIA Director
ATF
Movie • 1999
ATF Asst. Director Ben Walker
Crazy
Movie • 2008
Ralph Christianson
Victim of Love: The Shannon Mohr Story
Movie • 1993
Dick Britton
Secondhand Lions
Movie • 2003
Ralph
Indivisible
Movie • 2018
Chaplain Rogers
The Sunchaser
Movie • 1996
Agent Moreland
Jennifer Eight
Movie • 1992
Serato
Danger One
Movie • 2018
Beckwith
Ghost Story
Movie • 1981
Churchill
Sea of Love
Movie • 1989
Raymond Brown
Clemency
Movie • 2019
Chaplain David Kendricks
Lorenzo's Oil
Movie • 1992
School Psychologist
Beyond Betrayal
Movie • 1994
Ray Pasquerello
The Stand at Paxton County
Movie • 2020
Dell Connelly
J. Edgar
Movie • 2011
Senator McKellar
American Crime
Movie • 2004
Sheriff Smyth
Seabiscuit
Movie • 2003
Mr. Pollard
The Mod Squad
Movie • 1999
Greene
Cold Call
Movie • 2021
Christian
Awake to Danger
Movie • 1995
Detective Brickman
Standoff
Movie • 1998
Cult Leader (Voice)
Flying Lessons
Movie • 2010
Chief Dobbs
This Is Us
TV • 2016
Arlo
JAG
TV • 1995
Commander Bradley
The X-Files
TV • 1993
Patrol Captain Van Gelder
Roswell
TV • 1999
Philip Evans
Chicago Hope
TV • 1994
Bill Wyzinski
Ghost Whisperer
TV • 2005
Nolan
The Glades
TV • 2010
Trent Staley
Rizzoli & Isles
TV • 2010
Jonathan McKnight
24
TV • 2001
Richard Welsh
24
TV • 2001
Richard Walsh
Extant
TV • 2014
Alan Sparks
FlashForward
TV • 2009
CIA Director Keller
Law & Order: LA
TV • 2010
Jeb Monroe
Diagnosis: Murder
TV • 1993
Sheriff Buck O'Hara
Bates Motel
TV • 2013
Nick Ford
Manhattan
TV • 2014
Psychiatrist
The West Wing
TV • 1999
Ron Butterfield
Sons of Anarchy
TV • 2008
Anthony Franklin
The Mentalist
TV • 2008
Sheriff Nelson
Grey's Anatomy
TV • 2005
Gary Clark
11.22.63
TV • 2016
Arliss Price
One West Waikiki
TV • 1994
The Nine
TV • 2006
Pete Burton
Echoes
TV • 2022
Victor McCleary
Rectify
TV • 2013
Senator Roland Foulkes
Fringe
TV • 2008
Sheriff Velchik
Scandal
TV • 2012
Lonnie Mencken
The Resident
TV • 2018
Joshua Williams
Prison Break
TV • 2005
Herb Stanton
NCIS: Los Angeles
TV • 2009
Ret. U.S. Army General Richard Collins
NCIS
TV • 2003
Riley McCallister
ER
TV • 1994
Col. Ken Kilner
Commander in Chief
TV • 2005
Congressman Wilcox
The Unit
TV • 2006
Ron Cheals
Shooter
TV • 2016
Ray Brooks
Tom Clancy's Jack Ryan
TV • 2018
Senator Mitchell Chapin
Criminal Minds
TV • 2005
Det. Yarbough
Fire Country
TV • 2022
Harlan Denbo
Outer Range
TV • 2022
Judge Pettigrew
Leverage
TV • 2008
Judge Roy
The Romanoffs
TV • 2018
Ron Hopkins
Without a Trace
TV • 2002
Thomas Shannon
The Shining
TV • 1997
Daniel Edwards (uncredited)
S.W.A.T.
TV • 2017
Carl Luca
Crossing Jordan
TV • 2001
Chris Benz
Messiah
TV • 2020
Cameron Collier
LAX
TV • 2004
Alonso Mathews
Happy's Place
TV • 2024
Jim Jackoway
Millennium
TV • 1996
County Prosecutor Calvin Smith
Boston Public
TV • 2000
Dr. Bernard Colbert
Ally McBeal
TV • 1997
Dr. Colbert
The Practice
TV • 1997
Judge Robert Temple
Numb3rs
TV • 2005
Boyd Keene
Close to Home
TV • 2005
Don Wheeler
Happy Face
TV • 2025
D.A. Craig Calloway
Boston Legal
TV • 2004
Dr. Robert McLean
Army Wives
TV • 2007
Reverend Bankerd
CSI: Miami
TV • 2002
Jerry Blackburn