Dorothy Knowles was born in Unity, Saskatchewan in 1927. She studied biology at the University of Saskatchewan in Saskatoon from 1944- 1948. Following graduation she began a six-week summer course at Emma Lake organized by The University of Saskatchewan. Artist Reta Cowley from Saskatoon and James Frederick Finley from the Ontario College of Art taught the course.
When she returned to Saskatoon, she continued to study painting under Eli Bornstein and Nicholas Bjelejac at the University of Saskatchewan between 1948 and 1952. She also took a summer class at the Banff School in 1952. She then enrolled in The Goldsmith School of Art in London England.
In the 1960's, she attended numerous workshops led by painters such as Herman Cherry, the critic Clement Greenberg, Kenneth Noland, Jules Olitski, Lawrence Alloway, and Michael Steiner. All of whom had a significant influence on her work.
Knowles often works outdoors, at times completing entire paintings, or creating sketches and photographs to use in her studio. She works with oil, acrylic, watercolours, and charcoal.
Her work is part of both public, private, and corporate collections across Canada.
Knowles was awarded the Medal of Saskatchewan in 1987 and received the Order of Canada in 2004. She received an honorary degree from the University of Regina in 1994. She is also a member of The Royal Candian Academy of Arts.
She currently lives with her family in Saskatoon, Saskatchewan.