Bill de Blasio was sworn in as the 109th mayor of New York City today, becoming the first Democrat to occupy City Hall in nearly two decades.
Mr de Blasio took the oath of office moments after midnight in front of his Brooklyn home. His inauguration was to be celebrated on a far grander scale at noon (1700 GMT) on the steps of City Hall when he takes the oath again, administered by former President Bill Clinton.
The new mayor was elected two months ago by a record margin on the promise of being a sharp break from billionaire Michael Bloomberg. Mr Bloomberg leaves office after 12 years that reshaped New York, making it one of the nation's safest and most prosperous big cities but also one that has become increasingly stratified between the very rich and the working class.
Mr De Blasio, 52, was joined in the first minutes of 2014 by his wife, Chirlane McCray, and their two teenage children, a close-knit family who played a central role in his campaign and to some are a further symbol of a new era after the data-driven, largely impersonal Bloomberg years.
"To everyone, this is the beginning of a road we will travel together," Mr de Blasio said after taking the oath which was administered by New York State Attorney General Eric Schneiderman.
Dozens of staffers and supporters - including actor Steve Buscemi, former Vermont Governor Howard Dean and US Ambassador to South Africa Patrick Gaspard - braved freezing temperatures to crowd 11th Street in the Park Slope area.
Mr de Blasio waved to the crowd after taking the oath and hugged his wife and children, each dressed for the festive event: Chiara, 19, was wearing a party hat while Dante, 16, was sporting jeans.
Standing in the same spot where he launched his then-longshot mayoral bid in January, the new mayor signed the oath and paid the requisite nine dollar (£5.40) fee to the city clerk.
The inauguration signalled a joyous day for city Democrats, who outnumber Republicans in the city by a margin 6-to-1 but have been shut out of power since David Dinkins left office on New Year's Eve 1993.
Former Secretary of State Hillary Clinton, who is mulling a presidential run in 2016, also planned to attend today's ceremony at City Hall.
Both Clintons have ties to Mr de Blasio: the new mayor worked for the former president's administration in the Department of Housing and Urban Development and helped manage Mrs Clinton's successful 2000 Senate campaign.
Mr de Blasio, an unabashed progressive 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 Centre rises above the Manhattan skyline, symbolising the city's comeback from the September 11, 2001, terror attacks, many New Yorkers have felt left behind during the city's renaissance.
Mr de Blasio reached out to those he contended were left behind by the often Manhattan-centric Bloomberg administration, and he called for a tax increase on the wealthy to pay for universal pre-kindergarten.
He also pledged to improve economic opportunities in minority and working-class areas and decried alleged abuses under the police department's stop-and-search policy. He and his new police commissioner, William Bratton, have pledged to moderate the use of the tactic, which supporters say drives down crime but critics claim unfairly singles out blacks and Hispanics.