

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


Happy Face

Echoes

Extant

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
