Painter and printmaker Mary Henry was born Mary Dill in Sonoma, California, in 1913. She attended the California College of the Arts (then the California College of Arts and Crafts) in Oakland, California, studying under Ethel Abeel, Glen Wessels, and Marie Togni. She also worked for the Federal Art Project in the printmaking division. After winning a prize for printmaking sponsored by Iowa State University, she was invited to teach applied art in their home economics department, and she moved there with her husband Wilbur Henry in 1940. She taught there until the U.S. entered the war, at which point they returned to California and Wilbur enlisted in the military.

Henry took a job drafting engineering drawings for Hewlett Packard and enrolled in lithography courses at the San Francisco School of Fine Arts. During this time she attended a lecture by Laszlo Moholy-Nagy, which proved to be fortuitous; in 1945, she temporarily moved to Chiacgo to study under Moholy-Nagy at the Art Institute. She was keenly interested in the Bauhaus movement and studied the work of photographers, architects, and graphic designers, as well as painters, of Bauhaus. Her work, with its roots in social realism, now borrowed from her time in the WPA work as a draughtsman, finding freedom of expression in the playful geometry of Constructivism and Hard Edge. By the end of her enrollment the Institute made an offer of employment as a teacher - a first, as up until that point no other woman had been offered such a position there. However, feeling the constraints of family life, she decided to join her husband in Arkansas where he had been discharged to work with the U.S. Public Health Service, researching malaria. 

The Henry family returned once more to California in 1949, settling in Los Altos. There, Mary Henry joined the Local 510 Sign, Scene, and Pictorial Painters Union with the aim of creating a commerical career. She also began taking commissions for billboards, murals, and mosaics for private and corporate collections. It wasn't until 1964, when she and Wilbur divorced, that she began to focus on art for herself. She moved to the artist's hub of Mendocino, California, and set up a studio. To make ends meet she turned her home into the Sea Change Inn bed and breakfast, and she slowly began building an exhibition career.

By 1968 she was exhibiting at major galleries in the Bay Area, and one such show garnered a write up in Artforum magazine. Her style ranged from Construcivist to psychadelic, finding inspiration in the styles she had started pursuing in the 1940s as well as the current counter-culture works she was exposed to in 1960s and '70s San Francisco. Owing to her time as a engineering draughtsman many of her works exhibited an extraordinary mathematical geometry, often drawn free-hand onto the canvas or paper. 

Henry was active in art until well into her 90s. After traveling throughout Alaska in 1976 she settled permanently on Whidby Island in Washington. There, she took classes from Jack Tworkov, who would become a lifelong friend and who credited Henry with influencing his own work. She continued to paint until she could no longer stretch her own canvases, after which she worked in simpler mediums until her death of a stroke in 2011.