John Aylward, who starred in ER and The West Wing, died at the age of 75. According to Deadline, Aylward died overnight Monday at his home in Seattle.

His wife, Mary Fields, informed the magazine that her husband’s health was deteriorating. She informed his long-time agent, Mitchell K. Stubbs, of his death.

Stubbs told the outlet, ‘I was stunned.’ ‘He was a fantastic human being as well as a fantastic performer. He was a dream customer, friend, and guy.’

From 1996 through 2008, Aylward portrayed Dr. Donald Anspaugh on the hit medical series and former DNC head Barry Goodwin on The West Wing from 2005 to 2006.

Aylward was born and reared in Seattle, and her acting career began in the 1970s. His most well-known role, however, is that of Dr. Donald Anspaugh, a surgeon and hospital board member in ER.

Reports with a deadline Carol Flynt, co-producer of ER, spotted Aylward in a 1996 performance of Psychopathia Sexualis and gave him an audition for the position. For his performance in the play, Aylward got the Drama Logue Award for Outstanding Performance in 1996.

Aylward has also featured in television programs such as Alias, Cold Case, Boston Legal, Without a Trace, Nip/Tuck, The Practice, Everwood, The X-Files, Dharma & Greg, 3rd Rock from the Sun, Northern Exposure, The Mentalist, American Horror Story, Yellowstone, and Briarpatch.

He appeared in Water for Elephants, Down with Love, Armageddon, Teenage Mutant Ninja Turtles III, and Monster-in-Law as an uncredited priest.

He also provided the voice of Dr. Arne Magnusson in the computer game Half-Life 2: Episode Two After learning of Aylward’s passing, Stubb’s talent agency paid homage to him on Twitter.

‘I received a sad call from John Aylward’s wife, Mary Fields. This amazing actor and lovely man have passed away. Sir, I am grateful to have known and worked with you. RIP.’