Which U.S. president announced Japan's surrender in a national radio address in August 1945?

Harry S. Truman announced Japan's surrender in a national radio address in August 1945.

Truman was the 33rd president of the United States and had been president since April 1945, after Franklin D. Roosevelt died in office. On August 14, 1945, Truman announced that Japan had accepted the Allied terms of surrender. News of the announcement triggered celebrations across the United States and other Allied countries.

The timing explains why American sources often identify August 14 as V-J Day, while many other countries use August 15. Japan's announcement was broadcast in Japan at noon on August 15, which was still August 14 in parts of North America. The formal surrender documents were not signed until September 2.

Truman's announcement came after several extraordinary developments: the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war on Japan, and a final political struggle within Japan's leadership. Truman had authorized the use of atomic bombs after becoming president, inheriting the decision from the wartime administration.