Background
O'Neill was born and raised in Montgomery, Alabama.
O'Neill was born and raised in Montgomery, Alabama.
He attended Capitol Heights Junior High and Robert E. Lee High School, graduating in 1969. He graduated from Auburn University in 1974.
In high school he played basketball and was elected class beau and a class favorite. After attending Auburn, he spent time under the tutelage of actor Will Geer and one of Geer's daughters, the actress Ellen Geer, at Theatricum Botanicum in Los Angeles before moving to New York to pursue his career there. With a career stretching through three decades, he usually portrays senior law enforcement or military officers.
He played Special Agent Ron Butterfield, the head of President Josiah Bartlet's Secret Service detail, on The West Wing, and CTU Administrative Director Richard Walsh in the first two episodes of 24. He played Sgt. Maj. Ron Cheals in CBS' action drama series The Unit. 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, J. Edgar, directed by Clint Eastwood, and Dallas Buyers Club.