A celebrated artist and a dedicated teacher, Dempsey began carving in 1969 and was directed to the Gitanmaax School of Northwest Coast Indian Art in 1972 by Freda Diesing, who was his earliest mentor and teacher.
Dempsey's work is in the collections of the Canadian Museum of Civilization; the University of British Columbia’s Museum of Anthropology; the Columbia Museum of Ethnology; the Smithsonian Institution; National Museum of Ethnology in Japan; Canada House in London, England; Hamburgisches Museum fur Volkerskkunde in Hamburg, Germany; Centennial Museum in Ketchikan, Alaska, and the Royal British Columbia Museum. Corporate collections include the Vancouver International Airport, the Ridley Coal Terminal in Prince Rupert and the Saxman Tribal House in Saxman, Alaska.
He has pieces in numerous private collections including three significant collection in New York, San Francisco and Vancouver. All focus primarily on his work.