Michael O'Neill
Acting
🎂 1947-05-29
​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.
Cast credits(93)
Gary Clark
2005
Det. Yarbough
2005
Riley McCallister
2003
Nolan
2005
Herb Stanton
2005
Sheriff Nelson
2008
Ret. U.S. Army General Richard Collins
2009
Carl Luca
2017
Chris Benz
2001
Judge Robert Temple
1997
Jonathan McKnight
2010
Anthony Franklin
2008
Sheriff Velchik
2008
Patrol Captain Van Gelder
1993
Joshua Williams
2018
Senator Mitchell Chapin
2018
Arlo
2016
Richard Walsh
2001
Richard Welsh
2001
Sheriff Buck O'Hara
1993
Commander Bradley
1995
Ron Cheals
2006
Col. Ken Kilner
1994
Ron Butterfield
1999
Nick Ford
2013
Ray Brooks
2016
Judge Roy
2008
Thomas Shannon
2002
Judge Pettigrew
2022
Harlan Denbo
2022
Lonnie Mencken
2012
Trent Staley
2010
Ron Hopkins
2018
Arliss Price
2016
County Prosecutor Calvin Smith
1996
CIA Director Keller
2009
Alan Sparks
2014
Daniel Edwards (uncredited)
1997
1994
1994
Psychiatrist
2014
Congressman Wilcox
2005
Cameron Collier
2020
Philip Evans
1999
Dr. Bernard Colbert
2000
Pete Burton
2006
Alonso Mathews
2004
Senator Roland Foulkes
2013
Jim Jackoway
2024
Dr. Colbert
1997
Jeb Monroe
2010
Victor McCleary
2022
Joe Dean
2023
Frank
2025
Richard Barkley
2013
Lawyer Rodman
2000
Tom Banacheck
2007
Colonel Bethel
2010
Ralph
2003
O.B. Keeler
2000
Senator McKellar
2011
Raymond Brown
1989
School Psychologist
1992
Mr. Pollard
2003
General Matheson
2003
Ralph Christianson
2008
Serato
1992
Churchill
1981
CIA Director
2008
Chaplain David Kendricks
2019
Jon Jordan
1995
Greene
1999
Cowboy
2004
Agent Moreland
1996
Spencer Heymen
1994
1998
Beckwith
2018
ATF Asst. Director Ben Walker
1999
Cult Leader (Voice)
1998
Chaplain Rogers
2018
Jergens
1992
Clark Thompson
1993
Mr. Lusk
1998
Dell Connelly
2020
Sheriff Smyth
2004
Bruce
2008
Dick Britton
1993
Detective Simms
2014
Michael
1989
2025
Christian
2021
Detective Brickman
1995
Ray Pasquerello
1994
