Juan del Castillo enlisted in the Coast Guard in June 1942 after graduating from Manhattan College and, by mid-year, he had received appointment to Officer’s Candidate School at the Coast Guard Academy. He was commissioned an ensign in December of 1942, becoming the first Hispanic American to receive an officer’s commission. Castillo served on convoys in the Caribbean before receiving training at the Naval Communications School at Harvard University. The rest of the war saw him serving on board cutters in the North Pacific. Castillo was released from active duty in 1946 and served in the Reserves for nearly forty years. During this time, he had a distinguished career with the U.S. Department of Agriculture and became famous for developing “CSM,” a high-protein food substance used in disaster relief, famines and mass feeding operations.