Les Smith was born on October 31, 1918, in Mitchell, South Dakota. He graduated from Fresno State College in May 1940, and entered the Aviation Cadet Program of the U.S. Army Air Forces on November 7, 1941. Smith was commissioned a 2d Lt and awarded his pilot wings at Kelly Field, Texas, on July 3, 1942, and then joined the 61st Fighter Squadron of the 56th Fighter Group, deploying with the group to England in January 1943. While serving with the 61st Fighter Squadron, Maj Smith was credited with the destruction of 6 enemy aircraft in aerial combat plus 3 more damaged. He became commander of the 62nd Fighter Squadron of the 56th Fighter Group in September 1944, and destroyed 1 more enemy aircraft in the air before becoming Deputy Commander of the 56th Fighter Group in January 1945. During World War II, he was credited with the destruction of 7 enemy aircraft in the air plus 3 damaged, and another 4.5 on the ground while strafing enemy airfields. He transferred to the 65th Fighter Wing in England and served as Air Inspector from April to June 1945. Col Smith left active duty and joined the Air Force Reserve on January 10, 1946, serving until May 18, 1948, when he joined the California Air National Guard. He served as Commander of the 144th Fighter Group from May to July 1948, Commander of the 194th Fighter Squadron from July 1948 to April 1952, and Commander of the 144th Fighter Group from May 1952 to September 1955. Col Smith then served on the staff of the 144th Fighter Interceptor Wing from September 1955 to September 1957, followed by service as Deputy Commander of the 144th Air Defense Wing from September 1957 to January 1959. Gen Smith's final assignment was as Commander of the 144th Air Defense Wing from January 1959 until his retirement from the California Air National Guard on July 1, 1962.

His 4th (of 5) Distinguished Flying Cross Citation reads:

For extraordinary achievement and heroism in aerial combat and the destruction of two enemy airplanes over enemy occupied Continental Europe. The skillful and zealous manner in which Maj. Smith has sought out the enemy and destroyed him, his devotion to duty and courage under all conditions serve as an inspiration to his fellow flyers. His actions on all these occasions reflect the highest credit upon himself and the Armed Forces of the United States.