He attended St. Andrew's College from 1941 to 1946, graduating with the Class of 1946, and studied theatre at the University of Toronto.
In 1948, with his brother, Murray Edward Davis, he founded a summer theatre company, the Straw Hat Players, at Muskoka, Ontario.
In 1953, with his brother and sister (Barbara Chilcott), he founded the Crest Theatre in Toronto, which operated until 1966.
He was also a member of the acting company at the American Shakespeare Theatre in Stratford, Connecticut.
St. Andrew's College opened the Donald Davis Theatre posthumously in his honour.