With just four million votes between himself and Donald Trump, Joe Biden's victory was not by a landslide.
More than 70 million people voted for Donald Trump - that's more than for any other defeated candidate in history.
And for some of Trump's supporters, the fight for the presidency isn't over yet.
Azerbaijan's president has vowed to fight on until Armenian forces leave disputed territory, on the fourth day of fierce fighting in the region.
"We only have one condition: Armenian armed forces must unconditionally, fully, and immediately leave our lands," President Ilham Aliyev said.
More than 100 deaths have been reported in the heaviest fighting in years over the Nagorno-Karabakh region.
Officially part of Azerbaijan, it is governed by ethnic Armenians.
The two former Soviet republics fought a war in 1988-1994 over the territory. Although Armenia backs the self-declared republic it has never officially recognised it.
#BBCOS #BBCOutsideSource Joe Biden has said it is "time to heal" the US in his first speech as president-elect, vowing "not to divide but to unify" the country.
"Let's give each other a chance," he said at an event in Delaware addressing those who did not vote for him.
Mr Biden defeated incumbent President Donald Trump following a cliff-hanger vote count after Tuesday's election.
Mr Trump has yet to concede and has not spoken publicly since his defeat was announced while he was playing golf.
The result makes Mr Trump the first one-term president since the 1990s. His campaign has filed a barrage of lawsuits in various states but election officials say there is no evidence that the vote was rigged against him, as he has claimed.
Spontaneous celebrations erupted in major cities after media outlets announced Mr Biden's victory on Saturday. Disappointed Trump supporters demonstrated in some cities but there were no reports of incidents US President-Elect Joe Biden has spoken of his wish to "unify" the United States, in his first speech since his election win.
Some of those who voted for Joe Biden tell the BBC what their message would be to friends who supported Donald Trump.
Video by Shrai Popat and Holly Honderich The eldest son of Martin Luther King Jr talks about the upcoming US election as he tries to fulfil his father's vision for America.