After graduation from Boston English High School in 1942, Gray enlisted in the U.S. Army Air Corp as a private. After completing the College Training Detachment Program at Tuskegee Institute, he entered aviation cadet training to become a pilot. He graduated from the Tuskegee Army Air Filed Flying School as a 2nd Lieutenant Single Engine Pilot in Class 44-G (SE).

After completing combat fighter pilot training at Walterboro Army Air Field, Gray was stationed in Italy as a fighter pilot with the 100th Fighter Squadron, 332nd Fighter Group. He flew 15 combat missions over Europe in P-51 Mustangs. He had a total of 750 hours flying time. He was separated from active duty in 1946 and remained in the USAF Reserve until he retired in 1984. During his 41 years of military service, Lt. Col. Gray was awarded the Air Medal with one oak leaf cluster, a Presidential Unit Citation, and the Mediterranean Theatre of Operation ribbon with three battle stars. In addition, he earned the American Theatre and World War II Victory button.

Guest speakers are often invited to speak to the Cadets about aviation. Recently Col. Leo Gray addressed the group on April 17, 2007. He was a member of the famed Tuskegee Airmen, a group of African American pilots who flew with distinction during World War II.

Lieutenant Colonel Leo. R. Gray made significant contributions to the welfare of this country throughout his military and civilian careers. As a youth in the Boy Scouts of America, Gray met all qualifications for a Life Scout, and achieved the rank of Junior Assistant Scoutmaster in his Troop.