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Michael O'Neill

Acting · 1947-05-29 · 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.

Filmography (24)

YearFilmAs
2025Bride HardFrank
2025War of the WorldsSecretary of Defense Walter Crystal
2023AirJoe Dean
2013Dallas Buyers ClubRichard Barkley
2010Flying LessonsChief Dobbs
2010Green ZoneColonel Bethel
2008A Quiet Little MarriageBruce
2007TransformersTom Banacheck
2003DreamcatcherGen. Matheson
2003SeabiscuitMr. Pollard
2003Secondhand LionsRalph
2002The Emperor's ClubCo-Producer
2002The Board RoomWalters
2000The Legend of Bagger VanceO.B. Keeler
2000TrafficLawyer Rodman
1998Dancer, Texas Pop. 81Mr. Lusk
1998StandoffCult Leader
1996The SunchaserAgent Moreland
1992Lorenzo's OilSchool Psychologist
1992The Gun in Betty Lou's HandbagJergens
1992Jennifer EightSerato
1989Sea of LoveRaymond Brown
1989An Unremarkable LifeMichael
1981Ghost StoryChurchill