Diane Kay Corcoran was born in 1946 in Rochester, New York, where she also grew up. She attended the Genesee Hospital School of Nursing, where she signed up as a cadet in the United States Army Nurse Corps in her final year, joining the service full time upon her graduation in 1968.
Corcoran attended basic training at Fort Sam Houston in San Antonio, Texas. Her first assignment was to the Letterman Army Hospital of the Presidio in San Francisco, where she worked in a combined neurosurgery and intensive care unit. She then received orders to Vietnam, leaving on the 15th of August, 1969, spending approximately a year there. Upon returning to the United States, she took a year out of the service and obtained her Bachelor of Science in Nursing degree (BSN), and returned to service.
During the course of her service, Corcoran was also stationed at Redstone Arsenal in Huntsville, Alabama, and in 1976 became the chief nurse at the 86th combat support hospital at Fort Campbell, Kentucky. She also obtained her PhD, and retired in 1992 as a colonel.