Who is the only US president to serve two non-consecutive terms in office?

Grover Cleveland is the only U.S. president to have served two nonconsecutive terms in office because he was elected as the 22nd president in 1884, but lost his bid for reelection in 1888 to Benjamin Harrison. However, he successfully ran again in 1892 and became the 24th president, serving a second term. Cleveland's unique situation arose due to the split in his party, resulting in another candidate being nominated for one term before they turned back to Cleveland. This makes him the only president in American history to have left office and returned for a second term.