Robert Stephens was born on February 28, 1915, in Hobart, Oklahoma. He enlisted in the U.S. Army Air Corps in November 1939, and completed enlisted bombardier school in June 1940. Sgt Stephens next completed aircraft mechanic's school in February 1941, followed by service as a B-25 Mitchell bombardier with the 95th Bomb Squadron of the 17th Bomb Group at McChord Field, Washington, and then at Pendleton Army Airfield, Oregon, from February 1941 until he was selected for the Doolittle Mission in February 1942. Sgt Stephens was the bombardier on the fourth B-25 to take off from the aircraft carrier USS Hornet (CV-8) on April 18, 1942, and after bombing Tokyo his crew flew to China and bailed out when their aircraft ran out of fuel. He remained in the China-Burma-India Theater after the raid, and served as a B-25 bombardier with the 11th Bomb Squadron of the 341st Bomb Group in India from May 1942 to July 1943. After returning to the United States, SSgt Stephens was commissioned a Flight Officer in the U.S. Army Air Forces on February 11, 1944, and was rated as an Aircraft Observer. He was medically retired from the Army Air Forces on December 1, 1944. Robert Stephens died on April 13, 1959, and was buried at Rose Cemetery in Hobart, Oklahoma.

His Distinguished Flying Cross Citation reads:

For extraordinary achievement while participating in a highly destructive raid on the Japanese mainland on April 18, 1942. Sergeant Stephens 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 Sergeant Stephens and the military service.