Elaine Danforth Harmon was born in Baltimore, Maryland, in 1919, the second of three girls. Her father played professional baseball and was a dentist, and her mother was a housewife. Harmon graduated from Eastern High School in Baltimore in 1936 and then attended the University of Maryland. While there, Harmon joined the Civilian Pilot Training Program in College Park and got her private pilot's license. She graduated with a degree in microbiology in 1940.
Harmon was married on 26 July 1941 and traveled with her husband, often getting jobs related to serology, while he did civilian war work in the United States. At his encouragement, Harmon joined the WASP in March 1944. She attended WASP training at Avenger Field in Sweetwater, Texas, and graduated on 11 November 1944. Until the WASP disbanded on 20 December 1944, Harmon was stationed at Nellis Air Force Base in Las Vegas, Nevada, where she co-piloted with men practicing instrument flying.
Harmon returned to Baltimore in late 1944 and then went to California to work as an air traffic controller. She returned to Maryland in October 1945 when her husband returned from overseas. The Harmons settled in Silver Springs, Maryland, and raised four children. Elaine Harmon also had a twenty-five year career in real estate appraisal.