DiMaggio Joins the War EffortWhen the U.S. entered World War II nearly every American joined the war effort, including celebrities. One such was New York Yankee outfielder Joe DiMaggio. On February 17, 1943, 28-year-old Joltin’ Joe enlisted in the U.S. Army. Though he wouldn’t see any frontline action, he played the role of morale booster. His assignment: playing baseball on military teams in California and Hawaii.