In 1941, Hall enlisted in the U.S. Army Air Corps as an aviation cadet, he was assigned to Tuskegee, Alabama, to attend Advanced Flight Cadet Training at the Tuskegee Army Airfield. On July 3, 1942, Hall graduated from the program earning his wings and a commission as a 2nd Lieutenant. He was then assigned to the 332nd Fighter Group’s 99th Fighter Squadron. During World War II, Hall, nicknamed “Buster”, flew 198 missions over North Africa, Italy, the Mediterranean and Europe.
On his eighth mission in the European Theater/Mediterranean Theater on July 2, 1943, Hall and his squadron escorted B-25 medium bombers on a raid on Castelvetrano Airfield in southwestern Sicily, Italy. Flying in a P-40, Hall shot down a German Focke-Wulf Fw 190. Hall became first African American combat fighter pilot to shoot down an enemy aircraft.