Maggie Gee was born in Berkeley, California, August 5, 1923. She was a third-generation Chinese American; her maternal grandparents had moved to California from a village in Guangdong. In 1941, Gee enrolled at the University of California, Berkeley to study physics, but dropped out after a few months to work in the drafting department at the Mare Island Naval Shipyard, following the United States' entering World War II. She subsequently trained to become a WASP (Women Airforce Service Pilots).
After her service Gee returned to Berkeley, earned a bachelor’s degree in physics, then worked on weapons systems at the Lawrence Livermore National Laboratory.