With the outbreak of World War II, in 1939, he became Second Secretary in at the U.S. embassy in Cairo.[1] Given the strategic importance of Egypt during World War II, Hare played a critical role in moving American materiel to British forces in Egypt under the Lend-Lease program.[1] He later worked with the Persian Gulf Command in moving materiel to the Soviet Union by shipping it by rail through Iran following the Anglo-Soviet invasion of Iran.[1] During World War II, Hare became convinced of the strategic importance of the Middle East in the postwar period.[2]