He walked into one of the hardest gigs in television: replacing a fan-favorite character on a hit show already four seasons deep. When Wayne Rogers left M*A*S*H in 1975, Farrell stepped in as B.J. Hunnicutt and had to win over an audience still mourning Trapper John. He did it quietly, turning B.J. into the show's emotional anchor, the one who seemed most disturbed by the war. He was still there for the 1983 finale, which drew an estimated 106 million viewers.
Aside from a 2026 guest turn on 9-1-1, Farrell has spent the past three decades as president of Death Penalty Focus, the California advocacy group he's led since 1994. At 86, he's one of the last surviving lead cast members from M*A*S*H, alongside Alan Alda, Jamie Farr, and Gary Burghoff. A February 2025 sighting in Los Angeles had him wearing a 'Make America Normal Again' cap, which tells you exactly where his head is at.
Before M*A*S*H, he was a private investigator. Before that, a Marine. His father was a studio carpenter in Hollywood, which made him an industry kid who had to take the long way in. The strangest footnote came in 1985: sent to El Salvador as an Amnesty International observer, he reportedly ended up assisting with surgery on a wounded guerrilla commander. He married actress Shelley Fabares and wrote a memoir about all of it in 2007, Just Call Me Mike, because apparently the acting career was the least interesting part.