With 50.8% of the vote, President-elect Joe Biden has captured a second largest percentage of the vote than any challenger who has successfully ousted an incumbent president since 1840.
In the 1840 election, Whig challenger William Henry Harrison captured 52.9% of the vote versus incumbent Democrat Martin van Buren’s 46.8%.
The 1932 election saw Democrat Franklin Roosevelt swamp incumbent Herbert Hoover, 57% to 38%. (Thanks to @BlackCat for pointing out the omission in the original story.)
Even in the so-called “landslide” election of 1980, Republican Ronald Reagan only won 50.7% of the vote. Incumbent Democrat Jimmy Carter took just 41% of the vote, with independent John Anderson winning 6.6%.