'X-Files' Actor Peter Donat Dead at 90

Peter Donat, known for playing Agent Fox Mulder's father on The X-Files, passed away Monday at the age of 90.

The character actor known for his performances on both stage and screen died of complications from diabetes at his home in Point Reyes Station, California, as his wife Maria told The New York Times.

According to the outlet, despite being most known for his recurring role on the popular drama series — he appeared on six episodes — he preferred his work in theater. The actor frequently performed with companies like the American Conservatory Theater in San Francisco and the Stratford Festival in Canada. Over his career he embodied the roles of Cyrano de Bergerac, Prospero, Shylock, King Lear and Hadiran VII.

"It's the closest thing to the ideal creative life," he said of stage acting in an interview with The Honolulu Advertiser in 1984. "I mean, how often can an actor do Shakespeare, Chekhov and a new play, all in an eight-month span? And do TV shows and films in between?"

The Canadian-born performer was inspired to pursue a career in acting by his uncle, Robert Donat, a British actor known for his roles on Alfred Hitchcock's The 29 Steps, and Goodbye, Mr. Chips (1939), which earned him an Oscar win, according to The Hollywood Reporter.

Donat was married to The Waltons actress Michael Learned from 1956 to 1972. The couple met Francis Ford Coppola at the American Conservatory Theater in San Francisco, when the filmmaker later cast Donat in the role of Questadt in The Godfather: Part II (1974) and as an attorney in 1988's Tucker: The Man and His Dream.

THR reports the actor was considers for the role of Tom Hagen on the first Godfather film, though it ended up going to actor Robert Duvall.

The actor is also known for recurring roles on 1980 series Flamingo Road, starring Morgan Fairchild; and on classic drama series Dallas, where he played the doctor who treated Larry Hagman's character in 1980 during the resolution of the classic cliffhanger, "Who shot J.R.?"

The actor has numerous guest appearances on other television series including I Spy, Murder, She Wrote, Hawaii Five-O, Charlie's Angels, Hill Street Blues, Banacek, Medical Center and Mannix, McMillan & Wife.

Donat was born in Nova Scotia and studied at the Yale School of Drama. His career began in theater productions and was cast in his Broadway debut in 1957's The First Gentleman, Variety reports.

The actor is survived by his wife Maria; his sons Caleb, Christopher and Lucas; two stepdaughters, Barbara Park Shapiro and Marina Park Sutton; stepson Malcolm Park; 11 grandchildren and his brother and fellow actor Richard.