Blanche Holt Gwyn grew up in Mount Airy, North Carolina and graduated from Mount Airy High School. She earned a bachelor of science degree in secretarial administration from the Woman’s College of the University of North Carolina (now University of North Carolina at Greensboro) in 1936. She worked as a secretary in Mount Airy, but in 1939, she took a job with the Tennessee Eastman Company in Kingsport, Tennessee.
In July 1944, Gwyn took military leave from her job to join the WAVES (Women Accepted for Volunteer Emergency Service). She attended two months of Naval Reserve Midshipman School at Smith College in Northampton, Massachusetts. Her first duty station was at the Bureau of Ships in Washington, D.C. There she expedited equipment delivery to damaged ships. On 20 April 1946, she was discharged from the WAVES.
Gwyn spent twenty-three years in the Naval Reserve, first in a composite unit in New York and then in a telecom censorship unit in naval intelligence. In 1946, Gwyn went back to Eastman, this time working in advertising in New York City and later transferring back to Tennessee. She also attended Columbia University in New York City for a bachelor of arts degree and graduate studies in business. After retiring, Gwyn lived in Fancy Gap, Virginia, before returning to Mount Airy.