Corps of Engineers on graduation on 14 August 1932, ranking 19th in his class. He departed for England where he studied at Hertford College, Oxford, as a Rhodes Scholar. He was promoted to first lieutenant in August 1935, and awarded his Bachelor of Arts degree from Oxford. On returning to the United States, he was posted to the 8th Engineers at Fort McIntosh, Texas, as a troop commander. In June 1936 he became a student at the Massachusetts Institute of Technology, from which he graduated with a Master of Science degree in civil engineering in August 1937. He then became a student officer at the Engineering School at Fort Belvoir, Virginia. In June 1938, he reported to Vicksburg, Mississippi, as Assistant Project Engineer on the Sardis Reservoir Project. World War II McCormack reported to Fort Benning, Georgia, as a company commander in the 21st Engineers in October 1939. He was promoted to captain on 9 September 1940, and after serving as adjutant of the 20th Engineers at Fort Benning, he temporarily commanded one of the regiment's battalions before assuming command of the 76th Engineer Company at Fort McClellan, Alabama, in mid-1941. Later that year he attended the United States Army Command and General Staff College, after which he was promoted to major on 1 February 1942, and posted to the War Department General Staff. He was Assistant Chief of the Types and Allowances Branch of G-4 from March 1942 to March 1943, with a promotion to lieutenant colonel on 9 October 1942, and then Chief of the Construction Branch of G-4 from March 1943 to September 1943. In October 1943, McCormack became Chief of the Transportation Branch of the First United States Army Group, and was promoted to colonel on 1 December 1943. On 1 July 1944, he became the Chief of the Movements Branch of Twelfth United States Army Group, remaining in this role until 28 May 1945. For his services in the European Theater of Operations, he was awarded the Legion of Merit on 30 December 1944, and the Bronze Star Medal in May 1945. The British government made him an honorary Commander of the Order of the British Empire on 24 March 1945, while the French government awarded him the Croix de guerre with the silver star on 29 January 1945, and made him a Chevalier of the Legion of Honor on 3 October 1945. On 4