Zohran Mamdani was sworn in as mayor at a private ceremony at midnight, marking a historic moment for New York City.

Mamdani, a Democrat, was sworn in as the first Muslim leader of America’s biggest city, placing his hand on a Quran as he took his oath.

“This is truly the honor and the privilege of a lifetime,” Mamdani said in a brief speech.

The swearing-in, conducted by New York State Attorney General Letitia James, took place at a historic, out-of-use City Hall subway station.

In Mamdani's first remarks as mayor, he said the old subway station was a “testament to the importance of public transit to the vitality, the health and the legacy of our city" as he announced the appointment of his new Department of Transportation commissioner, Mike Flynn.

Mamdani will be sworn in again at 1 p.m. on the steps of City Hall, while his supporters are expected to crowd the Canyon of Heroes for an accompanying block party.

MORE: Power & Politics: Sit-down interview with Mamdani

The 34-year-old democratic socialist is the second youngest to ever be elected mayor of New York City. Mamdani is also the city’s first South Asian and Muslim mayor.

A former Queens assemblyman, he ran a mayoral campaign heavily focused on affordability. His signature proposals were free childcare, free city buses and a rent freeze for rent-stabilized apartments.