He went to work for the First National Bank in Hartley, Iowa, where his uncle was president, immediately after graduation and stayed until the United States joined World War I. After a great deal of persuasion, he worked for Herbert Hoover's Commission for Relief in Belgium, which began a lifelong friendship and collaboration. then served in the American Expeditionary Force with the 29th Engineers in France. After the war ended, Pate helped organize and direct efforts by the American Relief Administration to feed more than one million Polish children after the war.