After one season at Yale, Voigts entered the U.S. Navy during World War II. He was stationed at Great Lakes Naval Training Station outside of Chicago and served as a line coach on the base's Bluejackets football team from 1942 to 1943. When the war ended, Paul Brown, who had been head football coach at Great Lakes, hired Voigts as a tackle coach for the Cleveland Browns, a new team in the All-America Football Conference (AAFC) that was to start play in 1946. He joined the Browns in March 1945, making him the first assistant signed by the team.