Bill de Blasio took the oath of office administered by former President Bill Clinton on Wednesday, formally becoming the 109th mayor of New York City while pledging to pursue a sweeping liberal agenda.

The moment was the pinnacle of de Blasio’s unlikely political rise as a symbol of restoration for the city’s Democrats, who outnumber Republicans 6-to-1 in one of the nation’s most liberal cites yet have not controlled City Hall since 1993.

De Blasio, 52, was first sworn in 12 hours earlier at a brief modest ceremony outside his home in Brooklyn’s Park Slope neighborhood. Flanked only by his wife, Chirlane McCray, and their two teenage children, he was administered the oath by state Attorney General Eric Schneiderman, signed the official paperwork and, with a broad smile, paid the requisite $9 fee to the city clerk.

The events at City Hall were conducted on a far grander scale.

Clinton was joined by his wife, ex-Secretary of State Hillary Clinton, who is a presumptive White House front-runner in 2016. Another presidential candidate, Gov. Andrew Cuomo, also sat nearby, as did former Mayor Michael Bloomberg, just hours into his first day as a private citizen after spending 12 years in office.

Thousands of people braved cold New Year’s Day temperatures to salute the new mayor, who is slated to hold a receiving line in City Hall after the ceremony.

Two other Democrats were also sworn in to hold citywide offices: Letitia James as public advocate and Scott Stringer as comptroller.

The celebrities in attendance were not just confined to the political world: Singer Harry Belafonte opened the event, while actresses Cynthia Nixon and Patina Miller had starring roles. Scores of “everyday New Yorkers” took part, including 11-year-old Dasani, who was featured in The New York Times’ multipart series on homelessness from which de Blasio has repeatedly said he has drawn inspiration.

His first test in office will likely be delivered by Mother Nature: A significant snowstorm is expected to hit the five boroughs Thursday and Friday.

De Blasio, an unabashed liberal who touts his Brooklyn roots, takes office at a crucial juncture for the city of 8.4 million people.

As New York sets record lows for crime and highs for tourism, and as the nearly completed One World Trade Center rises above the Manhattan skyline, symbolizing the city’s comeback from the Sept. 11, 2001, terror attacks, many New Yorkers have felt left behind during the city’s renaissance.

De Blasio reached out to those he contended were lost during the often Manhattan-centric Bloomberg administration, and he called for a tax increase on the wealthy to pay for universal pre-kindergarten.

(AP)