Michael O'Neill

Michael O'Neill

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.

🎬 Movies Featuring Michael O'Neill

War of the Worlds

War of the Worlds (2025)

as Secretary of Defense Walter Crystal
Air

Air (2023)

as Joe Dean
Clemency

Clemency (2019)

as Chaplain David Kendricks
Indivisible

Indivisible (2018)

as Chaplain Rogers
The Grim Sleeper

The Grim Sleeper (2014)

as Detective Simms
J. Edgar

J. Edgar (2011)

as Senator McKellar
Green Zone

Green Zone (2010)

as Colonel Bethel
Crazy

Crazy (2008)

as Ralph Christianson
Transformers

Transformers (2007)

as Tom Banacheck
American Crime

American Crime (2004)

as Sheriff Smyth
Seabiscuit

Seabiscuit (2003)

as Mr. Pollard
Dreamcatcher

Dreamcatcher (2003)

as Gen. Matheson
Traffic

Traffic (2000)

as Lawyer Rodman
ATF

ATF (1999)

as ATF Asst. Director Ben Walker
Standoff

Standoff (1998)

as Cult Leader (Voice)
The Sunchaser

The Sunchaser (1996)

as Agent Moreland
Awake to Danger

Awake to Danger (1995)

as Detective Brickman
Beyond Betrayal

Beyond Betrayal (1994)

as Ray Pasquerello
Blind Justice

Blind Justice (1994)

as Spencer Heymen
Lorenzo's Oil

Lorenzo's Oil (1992)

as School Psychologist
Sea of Love

Sea of Love (1989)

as Raymond Brown