Five US presidential elections (so far) have elected presidents who received fewer votes than one of their opponents.
It’s election day in the United States. Most of the world will be watching the outcome with great trepidation, because this election will have worldwide consequences for era-defining crises like climate change, the pandemic, and the return of authoritarianism. If you have anxiety about this election, that’s completely reasonable and I won’t blame you for skipping this post.
One peculiar idiosyncrasy of the American electoral system is the Electoral College, a group of people chosen by the individual states to officially select the next president on the state’s behalf. In principle this means that every state can decide their own method of appointing electors and smaller states are not overwhelmed by the large population of other states. In practice, it means that some states have a much larger influence on the outcome of the election than others, and it’s possible for a candidate to lose despite having more overall votes. So far, five US presidents have been elected even though more people voted for their opponent.
1824. Four candidates received more than 10% of the vote each, at least in those states which recorded the popular vote. (At this time, six states had the local elected officials choose their delegation to the electoral college rather than directly polling the electorate.) The law said that lower-polling candidates had to be dropped and the electors would choose from the top three. That fourth candidate (Henry Clay) threw his electoral votes behind the second-place candidate, John Quincy Adams, who took the lead and became president. Adams immediately appointed Clay as Secretary of State. The first-place candidate, Andrew Jackson, ran against Adams in the next election and won.
1876. Rutherford Hayes (pictured above) receives a quarter million fewer votes than Samuel Tilden. Tilden received more electoral college votes, but four states’ votes were not part of that count because no-one could agree who had actually won them. Eventually a dirty deal was done: Hayes got to be president, but in return northern troops who were overseeing post-Civil-War Reconstruction in the south had to leave. As a direct consequence of that withdrawal southern states engaged in the systematic suppression of black votes in the south for decades afterwards.
1888. Benjamin Harrison loses the popular vote but picks up wins in key states – including New York – which led to an Electoral College victory over incumbent Grover Cleveland. Cleveland lost the presidency… but he returned four years later to win it again.
2000. Those of us old enough to remember this one are still sore about it. Al Gore won half a million more votes, but the deciding vote in the Electoral College came down to Florida – which had ridiculously thin margins between Gore and his opponent Bush. While those votes were being counted and recounted, the US Supreme Court ruled that counting must stop, and the merry-go-round settled on George W. Bush as the winner and president. Incredibly, it’s still not entirely clear who would have won Florida if the recounting had been allowed to continue, but it is likely that it would have been Gore.
2016. The current president of the United States lost the popular vote by nearly three million votes, making him the most unpopular president in American history. He has become more unpopular since then, for entirely good reasons.
The Generalist Academy 
No, it is indeed entirely clear that Gore won.
https://en.wikipedia.org/wiki/2000_United_States_presidential_election_recount_in_Florida#Post-election_studies
You might mention how close we are (so near but so far) to getting to the popular vote, without constitutional amendment:
https://en.wikipedia.org/wiki/National_Popular_Vote_Interstate_Compact
Once more than half the states (weighted by electors) sign on, it doesn’t matter what the rest do.
I love the Interstate Compact – it’s such a clever workaround for a broken system. But it does rely on those states who have previously signed on continuing to do so, and I believe that some of the state legislatures have shifted since their state signed on.