Mary Milton completed high school at St. Aloysius College, Adelaide and then studied art at the South Australian School of Arts and Craft. She became a lecturer there from 1958 to 1977. She also taught at the SA Institute of Technology and the Adult Education Department of the University of Adelaide. She has won numerous prizes for her artwork and is represented in municipal galleries and private collections throughout Australia.
Milton enjoys painting animals and birds, especially ducks and has said that the most important ingredient in her work is the detail which she eliminates. She focuses on character, form, colour, design and composition and stives for spontaneity in art.