Donald Trump was elected the 47th president of the United States on Wednesday (Nov 6), an extraordinary comeback for a former president who refused to accept defeat four years ago, sparked a violent insurrection at the US Capitol, was convicted of felony charges and survived two assassination attempts.

With a win in Wisconsin, Trump cleared the 270 electoral votes needed to clinch the presidency.

"It's a political victory that our country has never seen before," Trump told a victory party in Florida.

As supporters chanted "USA!", the 78-year-old added that his "magnificent" win would "allow us to make America great again."

World leaders swiftly pledged to work with Trump, led by Israel and Ukraine where the course of raging conflicts could depend on the new president and his isolationist "America First" foreign policy.

Vice President Kamala Harris, who only entered the race in July after President Joe Biden dropped out, ran a centrist campaign that highlighted Trump's inflammatory messaging and use of openly racist and sexist tropes.

But his apocalyptic warnings about immigration and championing of isolationism found their mark with voters battered by the post-COVID economy and eager for a change from the Biden years.

The campaign pointed to a nail-bitingly close contest, but the results came surprisingly fast, delivering a crushing victory that included wins in the swing states of Georgia, North Carolina and Pennsylvania.

Gloom descended on her campaign and Harris cut short a planned watch party and cancelled a speech. She is now due to speak later on Wednesday.