Mamdani, a 34-year-old democratic socialist, already faces intense scrutiny, even before taking office in one of the country’s most scrutinized political jobs. Republicans have cast him as a liberal boogeyman. Some of his fellow Democrats have deemed him too far left. Progressives are closely watching for any signs of him shifting toward the center.

On Jan. 1, he will assume control of America’s biggest city under that harsh spotlight, with the country watching to see if he can pull off the big promises that vaulted him to office and handle the everyday duties of the job. All while skeptics call out his every stumble.

For Mamdani, starting off strong is key, said George Arzt, a veteran Democratic political consultant in New York who worked for former Mayor Ed Koch.

“He’s got to use the first 100 days of the administration to show people he can govern,” he said. “You’ve got to set a mindset for people that’s like, ‘Hey, this guy’s serious.’”

That push should begin with Mamdani’s first speech as mayor, where Arzt said it will be important for the city’s new leader to establish a clear blueprint of his agenda and tell New Yorkers what he plans to do and how he plans to do it.

Mamdani will be sworn-in around midnight during a private ceremony at a historic, out-of-use City Hall subway station. Then in the afternoon, he will be sworn-in a second time on the steps of City Hall, while his supporters are expected to crowd surrounding streets for an accompanying block party.

From there, Arzt said Mamdani will have to count on the seasoned hands he’s hired to help him handle the concrete responsibilities of the job, while he and his team also pursue his ambitious affordability agenda.

Managing expectations as a movement candidate

Mamdani campaigned on a big idea: shifting the power of government toward helping working class New Yorkers, rather than the wealthy.

His platform — which includes free child care, free city bus service and a rent freeze for people living in rent stabilized apartments — excited voters in one of America’s most expensive cities and made him a leading face of a Democratic Party searching for bright, new leaders during President Donald Trump’s second term.

But Mamdani may find himself contending with the relentless responsibilities of running New York City. That includes making sure the trash is getting picked up, potholes are filled and snow plows go out on time. When there’s a subway delay or flooding, or a high-profile crime or a police officer parks in a bicycle lane, it’s not unusual for the city’s mayor to catch some heat.

“He had a movement candidacy and that immediately raises expectations locally and nationally,” said Basil Smikle, a Democratic political strategist and Columbia University professor, who added that it might be good for Mamdani to “Just focus on managing expectations and get a couple of good wins under your belt early on.”

“There’s a lot to keep you busy here,” he said.

A large part of Mamdani’s job will also be to sell his politics to the New Yorkers who remain skeptical of him, with Smikle saying “the biggest hurdle” is getting people comfortable with his policies and explaining how what he’s pushing could help the city.

“It’s difficult to have this all happen on day one,” he said, “or even day 30 or even day 100.”

Challenges and opportunities

Mamdani’s universal free child care proposal — perhaps one of his more expensive plans — is also one that has attracted some of the strongest support from New York Gov. Kathy Hochul, a moderate from Buffalo who endorsed the mayor-elect.

Hochul is eager to work with Mamdani on the policy and both leaders consider the program a top priority, although it’s not yet clear how exactly the plan could come to fruition. The governor, who is up for reelection next year, has repeatedly said she does not want to raise income taxes — something Mamdani supports for wealthy New Yorkers — however she has appeared open to raising corporate taxes.

“I think he has allies and supporters for his agenda, but the question is how far will the governor go,” said state Senate Deputy Leader Michael Gianaris, a Mamdani ally.

“There’s an acknowledgement that the voters have spoken, and there’s very clear policies that were associated with his successful campaign,” he said, “so to not make progress on them would be us thumbing our noses at the voters.”

Mamdani’s pledge to freeze the rent for roughly 1 million rent stabilized apartments in the city would not require state cooperation.

But that proposal — perhaps the best known of his campaign — is already facing headwinds, after the city’s departing mayor, Eric Adams, made a series of appointments in recent weeks to a local board that determines annual rent increases for the city’s rent stabilized units.

The move could potentially complicate the mayor-elect’s ability to follow through on the plan, at least in his first year, although Mamdani has said he remains confident in his ability to enact the freeze.

Other challenges await

His relationship with some of the city’s Jewish community remains in tatters over his criticisms of Israel’s government and support for Palestinian human rights.

The Anti-Defamation League, a prominent Jewish advocacy organization, plans to track Mamdani’s policies and hires as it pledged to “protect Jewish residents across the five boroughs during a period of unprecedented antisemitism in New York City.”

Earlier this month, a Mamdani appointee resigned over social media postsshe made more than a decade ago that featured antisemitic tropes, after the Anti-Defamation League shared the posts online.

The group has since put out additional findings on others who are serving in committees that Mamdani set up as he transitions into his mayoral role. In response, Mamdani said the ADL often “ignores the distinction” between antisemitism and criticism of the Israeli government.

The mayor-elect’s past call to defund the city’s police department continue to be a vulnerability. His decision to retain Jessica Tisch, the city’s current police commissioner, has eased some concerns about a radical shakeup at the top of the nation’s largest police force.

And then there’s Trump.

Tensions between Trump and Mamdani have appeared to cool — for now — after months of rancor led into a surprisingly friendly Oval Office meeting. Future clashes may emerge given the sharp political differences between them, particularly on immigration enforcement, along with anything else that could set off the mercurial president.