In early March 1941 construction began for Stephenville Army Air Base. In June 1941 the name was officially changed to Ernest Harmon Air Base, it was named after Captain Ernest Emery Harmon, an Army Air Corps pilot who was killed during a test flight in 1933.

Construction was completed in March 1943. Harmon Field was a major site through which the U.S. Army Air Force returned 240,000 American soldiers and other passengers to the United States. On July 26th 1947 the Department of the Air Force was created, Harmon became Ernest Harmon Air Force Base.

The 61st Flight Interceptor Squadron (FIS) was transferred from SAC to ADC in December 1948 at Selfridge AFB with F-80s. The squadron transitioned to F-86As in the fall of 1949 and to F-94Bs in the fall of 1950. In July 1953 control of the unit was transferred to North East Air Command with a move to Ernest Harmon Air Force Base. The unit flying F-89Ds was transferred back to ADC in April 1957. In October the squadron moved to Truax Field and transitioned to F-102As. On July 25th 1960 the 61st FIS was deactivated.

In the late 1950's Harmon became the home of 323rd F-102 Flight Interceptor Squadron. Over 40 KC-97 "Stratotankers" of the 376th Air Refueling Squadron of the 4081st Strategic Wing under the 8th Air Force, SAC were assigned as support.

Ernest Harmon Air Force Base officially closed on December 16th 1966.