Grew initially enjoyed postings to Cairo, Mexico City, Russia, Berlin, Vienna, and Denmark. He attended the 1919 Paris Peace Conference and the 1922–1923 Lausanne Conference on Near Eastern affairs. After serving as undersecretary of state from 1923 to 1927, in which capacity he helped to implement the 1924 Rogers Act's reorganization of the Foreign Service, Grew became ambassador to Turkey. In 1932, he was appointed the first career U.S. ambassador to Japan, remaining in Tokyo until Japan declared war on the United States in December 1941.
Grew's wife, Alice Vermandois Perry, was descended from Commodore Matthew Perry, who opened Japan to western influence in 1853. She had spent her youth in that country and knew many of its leading figures. Grew firmly hoped that Japan's growing antagonism toward the United States might be reversed. He urged greater American sympathy for Japan's economic problems and sought more latitude as ambassador in handling Japanese-American relations. Grew's regular swings from optimism to pessimism over each successive new Japanese government and his eagerness to conciliate successive new governments brought clashes with Stanley K. Hornbeck, head of the State Department's Division of Far Eastern Affairs.
Seeking to avoid what increasingly seemed to be an inevitable conflict, in October 1939 Grew publicly warned that, if Japan wished to avoid severe American retribution, it must alter its increasingly bellicose international stance. This precipitated harsh Japanese press attacks on him. Subsequently, he unsuccessfully urged a personal meeting between President Franklin D. Roosevelt and Japanese Premier Prince Konoe Fumimaro, which he later unconvincingly claimed might have averted war.
Interned after the Japanese attack on Pearl Harbor and repatriated to the United States in spring 1942, Grew returned to Washington as a special assistant to Secretary of State Cordell Hull, becoming director of the Division of Far Eastern Affairs in 1944. As undersecretary of state from December 1944 to August 1945, Grew opposed further collaboration with Soviet Russia, unsuccessfully sought to prevent the use of nuclear weapons against Japan by urging American acceptance of a negotiated peace settlement rather than unconditional surrender, and helped to preserve the Japanese emperor's status as nominal head of state. Grew retired in August 1945. He died at Manchester-by-the-Sea, Massachusetts, on 25 May 1965.
Bennett, Edward M. "Joseph C. Grew: The Diplomacy of Pacification." In Richard Dean Burns and Edward M. Bennett, eds., Diplomats in Crisis, 65–89. Wilmington, DE: Scholarly Resources, 1974.; Grew, Joseph C. Ten Years in Japan. New York: Simon and Schuster, 1944.; Grew, Joseph C. Turbulent Era: A Diplomatic Record of Forty Years. Walter Johnson, ed. 2 vols. Boston: Houghton Mifflin, 1952.; Heinrichs, Waldo H., Jr. American Ambassador: Joseph C. Grew and the Development of the United States Diplomatic Tradition. Boston: Little, Brown, 1966.; Nakamura Masanori. Japanese Monarchy: Ambassador Joseph Grew and the Making of the "Symbol Emperor System," 1931–1991. Armonk, NY: M. E. Sharpe, 1992.