Eisenhower was the only president to serve in both World War I & World War II.
President Mao
President Obama was born long after World War 2.
Kennedy (May 21, 1917)
H. Truman Eisenhower and FDR served just not overseas
President Woodrow Wilson was the president during World War 1. President Franklin Delano Roosevelt was the president during World War 2 until he died near the end of the war. President Harry S. Truman was president through the end of the war and during the Korean War.
John F. Kennedy was the only US President who served in World War II and whose boat was sunk by the Japanese.
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President Dwight D. Eisenhower.
President Woodrow Wilson declared war on German in World War 1 and was in office during the war.
President General Eisenhower.
Raymond Poincaré was President of France following the First World War.