Michael O'Neill
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
Dancer, Texas Pop. 81
Dallas Buyers Club
The Mod Squad
War of the Worlds (2025)
American Crime
Clemency
Nothing But the Truth (2008)
Joyride
The Sunchaser
Danger One
Secondhand Lions
Sea of Love
The Stand at Paxton County
Precious Find
Indivisible
Jennifer Eight
Demonwarp
Once Upon a Texas Train
Bride Hard
Dreamcatcher
The Legend of Bagger Vance
Bushwhacked
Seabiscuit
The Gun in Betty Lou's Handbag
Transformers
Green Zone
Blind Justice
Standoff
Happy's Place
Happy Face
Echoes