Born in Unity, Saskatchewan, Dorothy Knowles studied with Eli Bornstein and N. Bjelejac at the University of Saskatchewan, Saskatoon (B.A. 1944-1950); with Reta Cowley at Emma Lake Summer School (1948); at the Banff School of Fine Art (1949); at the Goldsmith School of Arts, London (1951); museum studies in England, France, Italy (1952); and with Clement Greenberg, Kenneth Noland, Jules Olitski and Michael Steiner at Emma Lake Workshops (1956-1988).
Working in oil, acrylic and watercolour, she painted abstract works before turning in 1962 to representational depictions of the Saskatchewan urban and rural landscapes in a style similar to watercolour sketches. She used the name Dorothy Perehudoff from 1952-1956. She taught at the University of Saskatchewan, Saskatoon (1968-1974) and at St. Peter's College, Muenster, Saskatchewan. She received a Canada Council award in 1966. She exhibited at the MMFA in 1968 and held solo exhibitions at the MAG in 1964,1968, 1969, and 1994 and at the EAG in 1973 and 1984. Her work is in the collections of the AGO, CCAB, EAG, GM, MAC, MAG, NMAG, SAB, WAG, and VAG.