Democrat Zohran Mamdani has been elected mayor of New York City, capping a stunning ascent for the 34-year-old state lawmaker, who will become the city’s most liberal mayor in generations.

In a win for the Democrats’ progressive wing, Mamdani soundly defeated former governor Andrew Cuomo and Republican Curtis Sliwa on Tuesday (local time).

In his victory speech, the new mayor said voters had “toppled a political dynasty”.

“I wish Andrew Cuomo only the best in private life. But let tonight be the final time I utter his name as we turn the page on a politics that abandons the many and answers only to the few,” he said.

“New York, tonight, you have delivered a mandate for change. A mandate for a new kind of politics. A mandate for a city we can afford. And a mandate for a government that delivers exactly that.”

It was one of just three major races won by the Democrats in the first elections since Donald Trump regained the US presidency, giving the beleaguered party a shot of momentum as it looks ahead to the congressional midterm elections in 2026.

Mamdani must now navigate the unending demands of America’s biggest city and deliver on ambitious — sceptics say unrealistic — campaign promises.

With the victory, the democratic socialist will etch his place in history as the city’s first Muslim mayor, the first of South Asian heritage and the first born in Africa.

He will also become the city’s youngest mayor in more than a century when he takes office on January 1.

Shortly after his victory was confirmed, Mamdani posted a video on X showing a subway carriage and a sign reading “City Hall” with a voiceover stating that “the next and last stop is City Hall”.

The mayoral race has made Mamdani a national figure as he has drawn the ire of Trump and other Republicans, who have tried to cast him as the face of a new, more radical Democratic Party.

Trump had also threatened to take over the city if Mamdani won, as well as arrest and deport the state assembly member, who was born in Uganda but is a US citizen.

Trump reluctantly endorsed Cuomo on the eve of the election, saying Mamdani would bring “disaster” to the city and encouraging Sliwa backers to vote for the former governor instead.

Mamdani proposes raising taxes on the richest New Yorkers and using the money to make city buses free and provide free, universal child care. He has also promised to freeze rent for people living in about a million rent-regulated apartments.

Cuomo, 67, positioned himself as a seasoned executive capable of managing the city’s vast bureaucracy, drawing a contrast with Mamdani’s relative inexperience.

Cuomo’s experience as governor was perhaps also his biggest vulnerability.

He resigned in 2021 following a report from the attorney general that concluded that Cuomo had sexually harassed at least 11 women.

Some of the women complained about unwanted touches, flirting, kisses and suggestive comments. One aide filed a police report accusing him of groping her breast, though a district attorney declined to prosecute.

Cuomo initially apologised for some of his behaviour, saying he had fallen out of step with what is considered appropriate workplace conduct.

However, in recent months, he has been defiant – calling his accusers liars and blaming his downfall on political adversaries.

Democrats win big

In other results on Tuesday, in Virginia and New Jersey, Democrats Abigail Spanberger and Mikie Sherrill won their elections for governor with commanding leads, respectively.

The contests offered a barometer of how Americans are responding to Trump’s tumultuous nine months in office

The races also served as a test of differing Democratic campaign playbooks ahead of 2026, with the party locked out of power in Washington and still trying to forge a path out of the political wilderness.

That said, the midterm elections are a year away, an eternity in the Trump era. And Tuesday’s contests all unfolded in Democratic-leaning regions that did not support Trump in the 2024 presidential election.

All three Democratic candidates emphasised economic issues, particularly affordability. But Spanberger and Sherrill hail from the party’s moderate wing, while Mamdani used a viral video-fuelled insurgent campaign to present himself as an unabashed progressive and a new generational voice.

Spanberger, who beat Republican Lieutenant Governor Winsome Earle-Sears, will take over from Republican Governor Glenn Youngkin in Virginia.

New Jersey’s Sherrill defeated Republican Jack Ciattarelli and will succeed Democratic Governor Phil Murphy.

Both Sherrill and Spanberger had sought to tie their opponents to Trump in an effort to harness frustration among Democratic and independent voters.

“We sent a message to the world that in 2025 Virginia chose pragmatism over partisanship,” Spanberger said in her victory speech. “We chose our Commonwealth over chaos”.

For Republicans, Tuesday’s elections were a test of whether the voters who powered Trump’s victory in 2024 will still show up when he is not on the ballot.

But Ciattarelli and Earle-Sears, both running in Democratic-leaning states, faced a conundrum: Criticising Trump risked losing his supporters, but embracing him too closely could have alienated moderate and independent voters who disapprove of his policies.

Trump remains unpopular: 57 per cent of Americans disapprove of his job performance, a Reuters/Ipsos poll showed.

But Democrats are not gaining support as a result, with respondents evenly split on whether they would favour Democrats or Republicans in 2026.

-with AAP