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(95)
Secretary of Defense Walter Crystal
2025
Gary Clark
2005
Riley McCallister
2003
Herb Stanton
2005
Det. Yarbough
2005
Sheriff Nelson
2008
Frank
2025
Carl Luca
2017
Ret. U.S. Army General Richard Collins
2009
Anthony Franklin
2008
Joshua Williams
2018
Richard Walsh
2001
Richard Welsh
2001
Nolan
2005
Patrol Captain Van Gelder
1993
Sheriff Buck O'Hara
1993
Thomas Shannon
2002
Sheriff Velchik
2008
Commander Bradley
1995
Ron Butterfield
1999
Lonnie Mencken
2012
Col. Ken Kilner
1994
Jonathan McKnight
2010
Arlo
2016
Chris Benz
2001
Judge Robert Temple
1997
Senator Mitchell Chapin
2018
1994
Boyd Keene
2005
Judge Roy
2008
Nick Ford
2013
Ray Brooks
2016
Philip Evans
1999
Ron Cheals
2006
Harlan Denbo
2022
Judge Pettigrew
2022
Alan Sparks
2014
Dr. Bernard Colbert
2000
County Prosecutor Calvin Smith
1996
Trent Staley
2010
Dr. Colbert
1997
Churchill
1981
Don Wheeler
2005
CIA Director Keller
2009
Joe Dean
2023
Jeb Monroe
2010
Arliss Price
2016
Psychiatrist
2014
Dick Britton
1993
Lawyer Rodman
2000
Senator Roland Foulkes
2013
Congressman Wilcox
2005
Gen. Matheson
2003
Cameron Collier
2020
Tom Banacheck
2007
Ralph
2003
Richard Barkley
2013
Colonel Bethel
2010
Ron Hopkins
2018
O.B. Keeler
2000
Alonso Mathews
2004
Senator McKellar
2011
Daniel Edwards (uncredited)
1997
Agent Moreland
1996
Mr. Lusk
1998
Mr. Pollard
2003
Victor McCleary
2022
Raymond Brown
1989
1994
School Psychologist
1992
CIA Director
2008
Jergens
1992
1998
Greene
1999
Pete Burton
2006
Sheriff Smyth
2004
Detective Simms
2014
Serato
1992
Detective Brickman
1995
Bruce
2008
Jon Jordan
1995
Spencer Heymen
1994
Michael
1989
Ralph Christianson
2008
Chaplain Rogers
2018
Cult Leader (Voice)
1998
Christian
2021
Chaplain David Kendricks
2019
Cowboy
2004
Jim Jackoway
2024
Dell Connelly
2020
Beckwith
2018
Clark Thompson
1993
ATF Asst. Director Ben Walker
1999
Ray Pasquerello
1994
