Benjamin Harrison was elected in 1888 as a so-called minority president, since he received fewer popular votes than the incumbent, Grover Cleveland, but won the electoral college. However, a look at state popular vote total suggest that the election might well have gone to Cleveland with the following swings (in round numbers!):
California 7000 (8 electoral votes)
Indiana 2200 (15 electoral votes)
Nevada 1900 (3 electoral votes)
New Hampshire 2400 (4 electoral votes)
Rhode Island 4000 (4 electoral votes)
That's a total of ~17,500 votes in about 11,000,000 cast, which could swing 34 electoral votes from Harrison to Cleveland. In turn, that would change the electoral count from 233 for Harrison to 168 for Cleveland in OTL to 199 for Harrison to 202 for Cleveland: a squeaker to end all squeakers but it would give Cleveland the election.
So: now that Cleveland has an uninterrupted tenure, what next?