Donald Smith was born on January 15, 1918, in Oldham, South Dakota. He was commissioned a 2d Lt of Infantry through the Army ROTC program at South Dakota State College in June 1940, and joined the Army Air Corps for flight training on July 26, 1940. Lt Smith was awarded his pilot wings at Kelly Field, Texas, on March 14, 1941, and then served with the 34th Bomb Squadron of the 17th Bomb Group at Pendleton Army Airfield, Oregon, from March 1941 until he was selected for the Doolittle Mission in February 1942. Lt Smith was the pilot aboard the 15th B-25 to take off from the aircraft carrier USS Hornet (CV-8) on April 18, 1942, and after bombing its assigned targets in Kobe, Japan, the crew ditched their aircraft in the water off the coast of China. He returned to the United States in June 1942, and served as a B-25 pilot with the 432nd Bomb Squadron of the 17th Bomb Group at Barksdale Field, Louisiana, from June to September 1942. His final assignment was as a B-26 Marauder pilot with the 439th Bomb Squadron of the 319th Bomb Group in England from September 1942 until he was killed in the crash of his B-26 on November 12, 1942. Donald Smith was buried at the Pine Slope Cemetery in Belle Fourche, South Dakota. He married Marie Crouch of San Antonio, Texas, on June 1, 1941, and they had one daughter together, Donna Marie Smith (born July 6, 1942, in San Antonio).

His Distinguished Flying Cross Citation reads:

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