NEW YORK — Zohran Mamdani, the democratic socialist who campaigned on a promise to tackle the affordability crisis in one of America’s most expensive cities, gave a soaring inaugural address on Thursday in front of thousands of New Yorkers and political luminaries including Senator Bernie Sanders, who swore him in.

Sworn in as New York City’s 112th mayor, Mamdani laid out what he called audacious plans to govern the city with a focus on working-class New Yorkers.

Mamdani, a 34-year-old immigrant from Uganda, makes history as the city’s first Muslim mayor, first South Asian mayor and the youngest mayor to hold the high-profile office in more than a century.

“My fellow New Yorkers, today begins a new era,” Mamdani said after his swearing-in.

In his speech Thursday, Mamdani spoke glowingly of the city he now leads, promising to be a mayor to all New Yorkers as he recalled taking the subway and bus as a teenager to his high school in the Bronx and his first date with his wife, Rama Duwaji, in Brooklyn’s McCarren Park.

“I know there are some who view this administration with distrust or disdain, or who see politics as permanently broken, and while only action can change minds, I promise you this: If you are a New Yorker, I am your mayor,” Mamdani said.

At the same time, Mamdani rejected any suggestions he would temper the ambitious agenda he set out in his campaign, pledging to bring down costs for everyday New Yorkers.

“Beginning today, we will govern expansively and audaciously. We may not always succeed, but never will we be accused of lacking the courage to try,” Mamdani said. “I was elected as a democratic socialist and I will govern as a democratic socialist. I will not abandon my principles for fear of being deemed radical.”

The former state assemblyman from Queens captured the world’s attention and stunned the political establishment with his win in the Democratic primary last summer, running a campaign focused on affordability: He promised to create a universal childcare program, freeze the rent for roughly two million rent-stabilized tenants and make city buses “fast and free.”

Among the thousands who attended Thursday’s ceremony were high-profile leaders of the progressive movement buoyed by Mamdani’s win, including Sanders and Democratic Rep. Alexandria Ocasio-Cortez.

Before swearing in the new mayor, Sanders thanked the tens of thousands of volunteers for his campaign who took on the Democratic and Republican establishments and “defeated them in the biggest political upset in modern American history.”

“Demanding that the wealthy and large corporations start paying their fair share of taxes is not radical, it is exactly the right thing to do,” Sanders said, as the crowd loudly chanted “tax the rich!”

Ocasio-Cortez, who won her own upset primary for Congress in New York in 2018, touted Mamdani as a mayor “relentlessly dedicated to making life not just possible, but aspirational for working people.”

“Zohran will be the first Muslim mayor of our great city. He will be our first immigrant mayor in over a century. And he will be the youngest mayor of New York City in generations,” she continued. “But most importantly, Zohran will be a mayor for all of us.”

The speakers who participated in Mamdani’s inauguration echoed many of the themes from his campaign and the larger progressive movement.

Cornelius Eady read a poem for Mamdani that he dedicated “to my trans, queer, foreign students of color at the University of Tennessee, Knoxville,” where he said he had recently retired, “so they can see this is possible.”

New York Public Advocate Jumaane Williams was sworn in by people impacted by immigration enforcement, including Senegalese immigrant Amadou Ly, whose speech introducing Williams drew a strong reaction from the inauguration crowd.

Other familiar faces present included former Mayor Bill de Blasio, who Mamdani has described as the best mayor in recent history. Outgoing Mayor Eric Adams was seated alongside de Blasio, with the crowd outside City Hall booing when Adams was shown on screen.

On Thursday, Mamdani signed several executive orders, including one that revoked all executive orders by his predecessor on or after September 26, 2024, when Adams was federally indicted on public corruption charges.

The Justice Department under President Donald Trump directed prosecutors to drop the charges against Adams earlier this year, and Adams has maintained he did nothing wrong.

Inside City Hall Plaza, the crowd began to gather early Thursday morning, bundled up in the freezing temperatures. A DJ attempted to keep the crowd warmed up as they waited for the ceremony to start.

A block party hosted by Mamdani’s transition team was held on Broadway, just outside the gates of city hall. The new mayor’s supporters lined the street behind barricades, many decked out in Zohran merchandise from his campaign and buttons that read, “NYC Inauguration 2026,” bearing the signature branding and color palette of Mamdani’s campaign.

New York resident Jen Shoemaker told CNN the crowd Thursday was "so energetic," adding, "We're so ready for Zohran."

“Everybody’s so energetic. We’re so ready for Zohran,” said Shoemaker, who arrived more than two hours before the inauguration began. “We need Democrats with backbones and Zohran has one.”

Mamdani was officially sworn in just after midnight during a private ceremony alongside his wife. His parents, filmmaker Mira Nair and Mahmood Mamdani, a professor at Columbia University, were also in attendance.

For the ceremony, Mamdani chose a Qur'an from the New York Public Library that was once part of Afro-Latino historian Arturo Schomburg’s personal library.

In a statement prior to the ceremony, the library said Mamdani’s selection of Islam’s holy book “marks a significant moment in our city’s history.”

It’s a choice steeped in meaning for Mamdani and the hundreds of thousands of Muslims who call New York City home. It’s the first time a Quran has been used in a mayoral inauguration.

Mamdani also used a Qur'an copy that belonged to his grandfather during the midnight ceremony, according to his transition team.

New York State Attorney General Letitia James, who Mamdani has described as a “political inspiration,” administered the oath of office as Mamdani placed his left hand on the two books.

The setting was symbolic. Mamdani was sworn in on the platform of the old City Hall subway station underneath City Hall Park in Manhattan – an architectural marvel where tiled, arched ceilings, colored glass skylights and brass chandeliers have laid dormant since the station was shuttered in 1945.

The location, which is closed to the public except for the occasional guided tour, is one of New York’s 28 original subway stations that opened in 1904, ushering in a new dawn of innovation and growth in New York City. — Agencies