William Stewart was born in Bridgeport, Connecticut. He grew up attending plays at the Yale Repertory. Stewart moved to San Diego, California, at the age of 21. He is an alumnus of Southwestern College and San Diego State University. He majored in psychology and was named to the national deans list honor roll and received the National Talented Minority Award.
His play Arthur´s Court, the life story of Arthur Ashe, made it to the semi-finals of the Eugene O´Neill Theatre Conference in Connecticut. In 2003, Stewart was invited to attend the Last Frontier Theatre Conference, and his short play The Drive was read. In 2004, a scene from American Plaza was performed at Southwestern College Theatre Summer Festival. In 2006, Stewart attended the first annual Great Plains Theatre Conference. That same year, he also submitted his play Remember…If It Happened to the Native Voice at the Autry in Los Angeles Development Workshop.