Veteran actor John Aylward, best known for his roles in the popular US TV shows ER and The West Wing has died aged 75.

The Seattle-born star was also a familiar face in a host of other hit American series during his career, including 3rd Rock From The Sun, Ally McBeal, The X-Files, Nip Tuck and Law & Order.

Aylward graduated from the University of Washington’s school of drama in 1970.

He got his start as a theatre actor, founding Seattle’s Empty Space Theatre in 1973 and was a regular in Seattle Repertory Theatre for 15 years.

After getting his start in television with small roles, his appearances grew during the 90s, and he secured a recurring part on Northern Exposure.

Aylward was cast in ER in 1996, during its third season, after co-producer Carol Flynt saw him perform on stage in Los Angeles.

He played Dr Donald Anspaugh, a leading board member of the central hospital, and the chief of staff and chief of surgery for much of the show’s run.

He appeared in more than 70 episodes of the series, making his final appearance in 2008 during the 15th and final season.

During the shooting of ER, Aylward also had a notable role the seventh and final season of The West Wing.

He played Democratic National Committee chairman Barry Goodwin, who advised the election campaign for president elect Matt Santos (Jimmy Smits), and eventually helped the transition between Josiah Bartlet (Martin Sheen) and Santos’ administrations.

Other notable television appearances include a main role in the short-lived science fiction show The Others, and a recurring spot in the US series Briarpatch.

Although best known for his roles on television, Aylward also had supporting roles in a number of films, including Teenage Mutant Ninja Turtles III, Armageddon and Down With Love.

Aylward, who died in his native Seattle of natural causes, is survived by his wife Mary Fields.