Lewis Walt was born on February 16, 1913, in Kansas. He graduated from the Colorado School of Mines in 1936 and that summer accepted a commission as a lieutenant in the Marine Corps. Walt saw combat in Tulagi, Guadalcanal, New Britain, and Peleliu during World War II and served with the Fifth Marines during Korea. He took command of the Third Marine Division in 1965 and the III Marine Amphibious Force in Vietnam. In 1967, Walt returned to the United States and after a stint as assistant commandant of the United States Marine Corps, he retired in 1971.