Aylward was born and raised in Seattle, Washington. He attended St. Josheph's Grade school and went on to Prep High School, but transferred and graduated from Garfield High School in 1965. He graduated from the Professional Actor's Training Program at the University of Washington in 1970. In 1973 he was one of the founders of Seattle's Empty Space Theatre and he worked regularly as a company member of the Seattle Repertory Theatre for 15 years until he became a television and film actor in the 1990s. He was first offered an audition for ER after he was seen by one of the co-creators in a 1996 production of Psychopathia Sexualis at the Mark Taper Forum in Los Angeles.