State Assemblyman Zohran Mamdani, the Democrats’ presumptive nominee for mayor of Wall Street’s home city, climbed atop a rooftop podium on election night, vowing a more socialist New York.

Backdropped by the Manhattan skyline, the 33-year-old had just dethroned the dynastic favored-to-win candidate, 67-year-old former Gov. Andrew Cuomo, in the mayoral primary and was declaring victory, outlining a vision for a city where child care and buses are free, rents are frozen, food is available at government-run groceries and the richest are taxed more.

Although the winner won't be formally declared until Tuesday under the city's ranked choice voting system, Mamdani appears to have an insurmountable lead, according to the Board of Elections website: 43.51% of first-choice votes to Cuomo’s 36.42%, with 11.31% going to Brad Lander, the city comptroller, with 96% of scanners reporting. And since Lander and Mamdani cross-endorsed each other, Lander voters are likely to have ranked Mamdani second.

Mamdani’s stunning rise from the left — and the unexpected fall Cuomo, backed by the likes of Bill Clinton and billionaires such as Mike Bloomberg, who gave millions to elect Cuomo — marks an unlikely toppling of establishment politicians and driven by young voters, not unlike the election that saw Rep. Alexandria Ocasio-Cortez in Queens, defeat the Queens Democratic Party boss, Joseph Crowley, in 2018.

Basil Smikle, the former executive director of the New York State Democratic Party, said he didn’t expect Mamdani to win — but he wasn’t surprised he did, observing a trend seen nationally, and locally with left-leaning candidates in the state legislature and New York City Council.

"You had a lot of younger voters who were really angry at the Democratic establishment and they were looking for some change. They wanted to go in a different direction," said Smikle, who once worked for Hillary Clinton and is now a Columbia University professor.

New York City’s incumbent mayor, Eric Adams, said the morning after the stunning upset that he can’t understand why anyone would vote for Mamdani, who is likely to be the Democrats’ nominee in the Nov. 4 general election.

"He’s a snake oil salesman," Adams said Wednesday on "Fox & Friends." "He would say and do anything to get elected."

On Wednesday, President Donald Trump posted on his Truth Social platform that "the Democrats have crossed the line" and that Mamdani is "a 100% Communist Lunatic."

"We’ve had Radical Lefties before," Trump’s post said, "but this is getting a little ridiculous."

Earlier this year, Adams withdrew from the Democratic primary after the city’s campaign regulator, citing allegations of fraud, including those that got him indicted, denied him all matching funds. Adams, who’s had senior staff resign over concerns he’s beholden to Trump due to the administration ordering the indictment dropped, is planning to run in the general election as an independent.

In contrast with Adams, who says he refuses to publicly criticize Trump and frequently praises the president and his policies — "hats off to U.S. Immigration and Customs Enforcement," Adams has said, as deportations in the city have accelerated — Mamdani has promised to fight back against Trump.

On Thursday, Adams is planning to "make a major announcement about the future of his reelection campaign," on the steps of City Hall at a "pivotal moment" to "set the stage for the next phase" of the race, his spokesman Todd Shapiro said in a news release. Specifics weren’t provided.

The founder of the neighborhood watch Guardian Angels, radio talk show host Curtis Sliwa, on Tuesday ran and won unopposed for the Republican nomination.

Cuomo conceded to Mamdani — "He deserved it. He won," Cuomo said at a union hall in Manhattan on election night — but he told CBS and other outlets he is considering an independent run. 

As "CUOMO FOR MAYOR" signs were being pulled down at the union hall, across the East River, Mamdani’s supporters were elated.

"He has a big mandate for change," Lander told Newsday. "People are hungry for a city New Yorkers can afford, and that’s gonna involve some big, bold changes, absolutely."

For his part, Mamdani says he wants New Yorkers to have "a city where they can do more than just struggle — one where those who toil in the night can enjoy the fruits of their labor in the day — where hard work is repaid with a stable life. Where eight hours on the factory floor or behind the wheel of a cab is enough to pay the mortgage."