Walter N. Stevenson, Jr. began his aeronautical engineering career at Consolidated Aircraft Company in San Diego, California in 1938. Educated in engineering at Northwestern University in his hometown of Evanston, Illinois, he became better known as "Big Steve" throughout his career. At Consolidated, he worked on the PBY Catalina and then transferred in 1942 to the Fort Worth, Texas plant.

He spent his career in Fort Worth at "The Bomber Plant" working for Convair and General Dynamics. During the 1940s he worked on armament features for the B-24, B-32 and B-36. During the 1950s he worked on the B-58 program including a joint design operation with General Electric for development of a new Gatling gun for defense aircraft use. This work evolved into the M61 20 mm Vulcan aircraft gun.

During the 1960s he became instrumental on the F-111 program where he reached the position of Program Director. He was pivotal to the program during the years the F-111 was involved with the Vietnam conflict. He was the Chief Project Engineer of the F-111 at the time of his retirement from General Dynamics in 1973.