John Aylward, Actor from ER and Armageddon , Dead at 75

Walter McBride/Getty

John Aylward, a prolific actor of stage and screen, has died. He was 75.

Aylward's agent Mitchell K. Stubbs confirmed the news in a message sent to PEOPLE, detailing that the actor died at his home in Seattle Monday of natural causes, according to his wife Mary Fields.

"John was a wonderful actor and a great friend to many," Stubbs wrote in the message. "He was proud of his film and television work although his life in the theatre was where he was the happiest. He was a good man."

RELATED: Andy Griffith Show Star Maggie Peterson Dead at 81

Aylward's standout performances in television include the recurring role of Dr. Anspaugh on ER, the surgeon and leading hospital board member at County General Hospital who was often at odds with the other doctors.

He also played former DNC chairman Barry Goodwin over six episodes of The West Wing between 2005 and 2006.

RELATED VIDEO: Gilbert Gottfried, Aladdin Voice Actor and Comedian, Dead at 67 'After a Long Illness'

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Some of Aylward's other guest or recurring TV credits include Northern Exposure, 3rd Rock from the Sun, Ally McBeal, The X-Files, The Practice, Judging Amy, Alias, Nip/Tuck and Shameless.

On the film side, Aylward is known for appearances in Armageddon in 1998, Instinct the following year, and 2010's The Crazies starring Timothy Olyphant.

His most recent credits include 2020's The Way Back with Ben Affleck as well as Briarpatch, in which he played Freddie Laffter in the series starring Rosario Dawson.

RELATED: Fred Ward, Famed Character Actor, Dead at 79

Aylward was a founding member of Seattle's Empty Space Theatre in 1973, and was also a company member of the Seattle Repertory Theatre for 15 years.

Stubbs also tweeted about the actor's death on Wednesday, writing, "This kind man and wonderful actor has left us. Very grateful to have known and worked with you, sir. RIP"