Harry S. Truman was U.S. president when Japan accepted the Allied surrender terms in August 1945.
Truman became president on 12 April 1945 after Franklin D. Roosevelt died. During Truman’s presidency, the United States continued the war against Japan, used atomic bombs against Hiroshima and Nagasaki, and received Japan’s acceptance of the Potsdam Declaration in August.
Truman publicly announced Japan’s surrender decision in the United States on 14 August 1945. The formal surrender ceremony followed on 2 September aboard USS Missouri in Tokyo Bay. Truman remained president during the opening phase of the Allied occupation of Japan.
Roosevelt was president for most of World War II but died before Germany surrendered and before Japan accepted the Allied terms. Winston Churchill was the British prime minister for much of the war, although Clement Attlee replaced him in July 1945. These differences make the presidential timing important.