Step 1: Understand the U.S. Presidential Term Limit
The U.S. Constitution now limits a President to two terms, but this was formally set by the 22nd Amendment in 1951. Before that, there were no term limits.
Step 2: Identify President Before the Amendment
Franklin D. Roosevelt was elected before the 22nd Amendment was in place.
Step 3: Verify Duration
FDR served four terms from 1933 to 1945, the only U.S. President to do so. He led the country through the Great Depression and World War II.
Step 4: Eliminate Options
Barack Obama and Bill Clinton each served 2 terms.
Ronald Reagan served 2 terms as well.
Thus, Franklin D. Roosevelt is the only one who served more than two terms.