Which U.S. president announced V-J Day in the United States in 1945?

Harry S. Truman announced V-J Day in the United States in 1945.

Truman was the U.S. president when Japan accepted the Allied terms and when the formal surrender ceremony was held. He publicly declared 2 September 1945 to be V-J Day, although he carefully noted that the formal proclamation ending the war and the cessation of hostilities had not yet occurred at the time of his initial announcement.

The date produced different observances because news traveled across time zones. Japan and many British Commonwealth countries focused on 15 August, when Hirohito's surrender message was broadcast. In the United States, the announcement arrived on 14 August local time, while the formal ceremony occurred on 2 September.

Truman had become president only in April 1945 after Franklin D. Roosevelt died. He therefore directed the final U.S. wartime decisions against Japan, including the administration's response to the surrender and the beginning of the postwar transition.

V-J means “Victory over Japan,” paralleling V-E Day, the Allied celebration of victory in Europe.