FDR served as POTUS during WWII.
There was no single leader during WW1. Each country had their own leader.
wwii- adolf hitler.
Joseph Stalin (aka Ioseb Besarionis dze Jughashvili) was the paramount leader of the USSR who held the position of: General Secretary of the Communist Party of the USSR Premier of the USSR Marshal of the Soviet Union (aka Generalissimo) during the Second World War.
During World War I, the National Socialist German Workers' Party (NSDAP), commonly known as the Nazi Party, did not have a prominent leader, as it was not yet a significant political force. The party was founded in 1920, after the war had ended. The most notable figure associated with the party, Adolf Hitler, joined in 1919 and later became its leader in the early 1920s.
Franz Josef
Roosevelt
The most powerful leader in Russia during World War I was Nicholas II. In addition, Nicholas Nikolaevich and Aleksei Brusilov were leaders during WW1.
President truman
Emperor HiroHito
Winston Churchill .
FDR
FDR
Franklin D. Roosevelt
Joseph Stalin was the leader of the Soviet Union during World War II.
Admiral Chester Nimitz (for most of the war)
Hideki Tojo was the leader of japan in world war 2.
There was no single leader during WW1. Each country had their own leader.