At the age of 16, Stewart left Busselton to work for the Western Australian Bank. In 1940 he enlisted in the Royal Australian Air Force, and was appointed an officer in No. 5 Initial Air Training School. When the war ended, Stewart returned to the family business in early 1946. The following year, he decided to seek election as a Liberal Party candidate to Parliament for the State electoral seat of Sussex (now Vasse). He was duly elected and represented the Sussex electorate as the Legislative Assembly Member for 24 years.
His brother Reg Bovell returned to Busselton in 1947 with his wife Grace (nee Edwards), to take over from Stewart as shipping agent. On his retirement from the State political arena in 1971, Stewart served as Agent General in London until 1974. He was knighted in the 1976 Queen’s Birthday Honours.
In retirement he and his wife Amy returned to their gracious home in West Street, Busselton, where he supported many community groups and he was particularly interested in youth issues and activities.