Mary Jane DeWan of Franklin Park, Illinois, graduated from high school in River Forest in 1938. She attended nurses training at Oak Park Hospital in Oak Park, Illinois, finishing in June 1941. She then served briefly as a registered nurse at the Loyola University Hospital in Illinois.
DeWan joined the ANC in August 1942. She was sent to Camp Swift in Bastrop, Texas, as a second lieutenant, and then in June 1943 was assigned to Fort Leavenworth, Kansas, in preparation for overseas duty. In September 1943, she married John DeWan, and in November she left Camp Stoneman in San Francisco, California, for Brisbane, Australia.
In January 1944, DeWan departed Australia for Oro Bay, New Guinea, where she was assigned to the 10th Station Hospital. In September 1944, she went to Finschhafen, New Guinea, and a few months later when her unit was changed to the 1st Field Hospital, she traveled to Leyte, Philippines, via Biak, New Guinea, and Peleliu in the Palau Islands. In August 1945, DeWan was stationed at Mindanao, Philippines. She stayed there until November 1945 when she returned to the United States. DeWan was discharged from the army in March 1946, and she and her husband returned to Illinois. She returned to nursing twenty-five later and worked for a decade before retiring.