After his studies McIntyre joined the Merchant Marine, and when World War II broke out, he served for four years with the U.S. Navy in the Pacific theater. During his Merchant Marine and Naval careers, McIntyre circumnavigated the globe, visiting countries such as Japan, China, Manchuria, Singapore, India and Brazil. After the war, McIntyre was assigned to the Peruvian Navy as a gunnery adviser, retiring with the rank of captain.
