After the war, Johnson became the chief test pilot for Republic Aviation, maker of the P-47, where he worked as an engineering executive for 18 years, and served as national president of the Air Force Association from 1949–1951. He remained a member of the US Air Force Reserve, visiting Air Force bases in South Korea in December 1951, and retired as a lieutenant colonel in 1962 from the Air Force Reserve. In 1964 Johnson became an insurance executive in Lake Wylie, South Carolina.