
Montgomery, Alabama, USA
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.

as Sheriff Nelson

as Gary Clark
2005

as Riley McCallister
2003

as Sheriff Nelson
2008

as Det. Yarbough
2005

as Carl Luca
2017

as Herb Stanton
2005

as Jerry Blackburn
2002

as Richard Walsh
2001

as Buck Avery
2024

as Anthony Franklin
2008

as Ret. U.S. Army General Richard Collins
2009

as Senator Mitchell Chapin
2018
as Joe Dean
2023

as Secretary of Defense Walter Crystal
2025

as Frank
2025

as Joe Dean
2023

as Christian
2021

as Dell Connelly
2020

as Chaplain David Kendricks
2019

as Chaplain Rogers
2018

as Beckwith
2018

as Detective Simms
2014

as Richard Barkley
2013

as Senator McKellar
2011

as Colonel Bethel
2010

as Chief Dobbs
2010

as CIA Director
2008

as Bruce
2008

as Ralph Christianson
2008

as Tom Banacheck
2007

as Cowboy
2004

as Sheriff Smyth
2004

as Ralph
2003

as Mr. Pollard
2003

as Gen. Matheson
2003

as Lawyer Rodman
2000

as O.B. Keeler
2000
as Sheriff Nelson
1 ep.

as Gary Clark
4 episodes

as Riley McCallister
3 episodes

as Sheriff Nelson
1 episodes

as Det. Yarbough
1 episodes

as Carl Luca
3 episodes

as Herb Stanton
1 episodes

as Jerry Blackburn
1 episodes

as Richard Walsh
1 episodes

as Buck Avery
1 episodes

as Anthony Franklin
1 episodes

as Ret. U.S. Army General Richard Collins
1 episodes

as Senator Mitchell Chapin
5 episodes

as Patrol Captain Van Gelder
1 episodes

as Col. Ken Kilner
1 episodes

as Joshua Williams
1 episodes

as Sheriff Velchik
1 episodes

as Commander Bradley
1 episodes

as Ron Butterfield
15 episodes

as Thomas Shannon
1 episodes

as Arlo
1 episodes

as Nolan
1 episodes

as Sheriff Buck O'Hara
1 episodes

as Lonnie Mencken
5 episodes

as Dr. Robert McLean
1 episodes
Co-Producer