Paul Leonard was born on June 28, 1914, in Roswell, New Mexico. He enlisted in the U.S. Army Air Corps on July 13, 1931, and was trained as an airplane mechanic. Leonard served at bases in Texas, Illinois, and Colorado before being assigned to the 37th Bomb Squadron in May 1941. SSgt Leonard was the Engineer-Gunner on the first B-25 to take off from the aircraft carrier USS Hornet on April 18, 1942, and after bombing Tokyo his crew flew to China and bailed out when their aircraft ran out of fuel. Leonard remained in China until June 1942, and then returned to the United States to serve as General Doolittle's personal crew chief. He served in England and North Africa from September 1942 until he was killed in action in Algeria on January 5, 1943. Paul Leonard was originally interred in Tebessa, Algeria, but his remains were later returned to the United States and buried at the Santa Fe National Cemetery in Santa Fe, New Mexico.

His Distinguished Flying Cross Citation reads:

For extraordinary achievement while participating in a highly destructive raid on the Japanese mainland on April 18, 1942. Staff Sergeant Leonard volunteered for this mission knowing full well that the chances of survival were extremely remote, and executed his part in it with great skill and daring. This achievement reflects high credit on Staff Sergeant Leonard and the military service.