Marion Walton was born in 1905 in New Rochelle, New York, the daughter of Ernest Forster Walton and music patron Blanche Wetherill Walton. During the 1920s, she studied at the Art Students League and, from approximately 1922 to 1924, at the Académie de la Grande Chaumière in Paris under sculptor Antoine Bourdelle. One of her classmates was Alberto Giacometti.
In 1933, Walton had a solo exhibition at the Weyhe Gallery and later participated in numerous group exhibitions primarily in New York City and in Paris, France. Her work is represented in private collections in the United States and abroad, and in the museum of the University of Nebraska.
Walton taught students in her studio in New York City and at Sarah Lawrence College. She was also a member of Artists Equity and a charter member of the Sculptors Guild.
Walton was married to James Putnam, assistant to the President of the publishing house, MacMillan Company.
Marion Walton died in 1996.