He initially enlisted in the reserves of the Signal Corps of the United States army.
He rose to 1st lieutenant after later enlisting in the United States Army Air Corps, assigned to Kelly Field.
He submitted his drawings to Brigadier General Frank P. Lahm, who was sufficiently impressed to have Clark detailed to work for him as Randolph Air Force Base was built.
[2] His design of the Administration Building became known as the Taj Mahal and was added to the National Register of Historic Places in 1987.
[5] Clark served at various U.S. Air Force installations over the next two decades, and during World War II became commander of 52nd Troop Carrier Wing, Army Air Base at Pope Field in North Carolina, and the Troop Carrier Wing in the North African Theater of Operations.