Michael O'Neill
Biography
Michael O'Neill, born on May 29, 1951, is a seasoned American actor with a career that has spanned over thirty years. He is widely recognized for his portrayal of senior law enforcement and military figures. One of his most prominent roles was as Special Agent Ron Butterfield, who led President Josiah Bartlet's Secret Service detail on the acclaimed series The West Wing. O'Neill also appeared as CTU Administrative Director Richard Walsh in the pilot episodes of the hit show 24 and played Sgt. Maj. Ron Cheals in the CBS action-drama The Unit. In a memorable performance on Grey's Anatomy, he portrayed a grieving widower who takes the hospital hostage while seeking justice for his wife's fate.
Throughout his film career, O'Neill has delivered notable performances in a variety of movies, including Seabiscuit, Secondhand Lions, Transformers, and Traffic, among others. His diverse filmography also includes roles in Sea of Love, A Quiet Little Marriage, Nothing But the Truth, and Green Zone.
O'Neill graduated from Auburn University in 1974, after which he trained under the guidance of actor Will Geer and his daughter, Ellen, at Theatricum Botanicum in Los Angeles. He later relocated to New York to further his acting career, establishing himself as a talented and versatile performer in both television and film.
Filmography
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Dancer, Texas Pop. 81
1998 • Mr. Lusk
Dallas Buyers Club
2013 • Richard Barkley
The Mod Squad
1999
War of the Worlds (2025)
2025 • Secretary of Defense Walter Crystal
American Crime
2004 • Sheriff Smyth
Clemency
2019 • Chaplain David Kendricks
Nothing But the Truth (2008)
2008
Joyride
1977
The Sunchaser
1996 • Agent Moreland
Danger One
2018 • Beckwith
Secondhand Lions
2003
Sea of Love
1989
The Stand at Paxton County
2020 • Dell Connelly
Precious Find
1996
Indivisible
2018 • Chaplain Rogers
Jennifer Eight
1992 • Serato
Demonwarp
1988
Once Upon a Texas Train
1988
Bride Hard
2025 • Frank
Dreamcatcher
2003 • Gen. Matheson
The Legend of Bagger Vance
2000
Bushwhacked
1995