Born in Claremont, Ontario, Thomson studied law at the University of Seattle, Washington (1901) as well as at the Art Students’ League, NYC (1906-1907). He also studied under F. Dumond in Old Lyme, Connecticut. Working in oil, he is known for his Northern Ontario landscapes and Ontario farm scenes. He painted in Parry Sound, Brandy Lake, Muskoka, Georgian Bay, and Haliburton, Ontario. He lived in New Haven, Connecticut (1910-1926) and then in Owen Sound, Ontario where he later died. Thomson was the brother of Tom and Fraser Thomson. He was a member of the Connecticut Academy of Fine Arts, and the New Haven Paint and Clay Club. He exhibited with the RCA from 1918-1950 and with the AAM in 1929-1940. His work is in the collections of the AGO and NGC.