Roosevelt was educated at private academies and Harvard University; after his 1909 graduation from college, he began a successful career in business and investment banking. Having gained pre-World War I army experience during his attendance at a Citizens' Military Training Camp, at the start of the war he received a reserve commission as a major. He served primarily with the 1st Division, took part in several engagements including the Battle of Cantigny, and commanded the 26th Infantry Regiment as a lieutenant colonel. After the war, Roosevelt was instrumental in the forming of the American Legion.