Matthew Ridgway
Major Clark served as a deputy commander of the Civilian Conservation Corps district in Omaha, Nebraska, in 1935–1936, between tours at the U.S. Army Command and General Staff School in 1935 and the U.S. Army War College in 1937. Among his classmates there were Matthew Ridgway, Walter Bedell Smith and Geoffrey Keyes, all of whom he would serve with during World War II.