Harry S. Truman announced Japan’s surrender to the American public in August 1945.
Truman became president after Franklin D. Roosevelt died in April 1945. As president, he oversaw the final months of the war, including the Allied demand for Japan’s surrender and the atomic bombings of Hiroshima and Nagasaki.
On August 14, 1945, Truman announced that Japan had communicated its acceptance of the Potsdam Declaration through diplomatic channels. Because of the International Date Line and other time-zone differences, the announcement was heard in Japan on August 15.
Truman distinguished the announcement from the formal end of the war. He stated that the official proclamation of V-J Day would wait for Japan to sign the surrender terms. That signing occurred aboard USS Missouri on September 2, 1945. This is why August and September dates can both appear in accounts of V-J Day.