William Henry Harrison spent the shortest time in office, and Franklin D. Roosevelt spent the longest. He is the only president to have served more than two terms. Following ratification of the 22nd Amendment in 1951, presidents -- beginning with Dwight D. Eisenhower -- have been ineligible for election to a third term or for election to a second full term after serving more than two years of a term to which some other person was elected president. The amendment contained a grandfather clause that explicitly exempted the incumbent president -- then Harry S. Truman -- from the new term limitations.
who served the least amount of time as president
William Henry Harrison