Final answer:
Grover Cleveland was the first and only U.S. president to serve non-consecutive terms, becoming both the 22nd and 24th president.
Step-by-step explanation:
The first and only U.S. president to serve non-consecutive terms was Grover Cleveland. Cleveland became the 22nd president, serving from 1885 to 1889, and then again as the 24th president from 1893 to 1897. He's notable for being the only president in American history to leave the White House and return for another term four years later after being defeated in the intervening election. Cleveland was elected as the 22nd president in 1884, but lost his re-election bid in 1888 to Benjamin Harrison. However, Cleveland won again in 1892, making him the first president to serve two non-consecutive terms.