Mayor Bill de Blasio pledged on Wednesday to see through his campaign promise for a "fairer, more just, more progressive" New York City at an inauguration ceremony on the steps of City Hall, now occupied by its first Democratic mayor in 20 years.

"When I said we would take dead aim at the tale of two cities, I meant it," de Blasio said to cheers. "And we will do it. I will honor the faith and trust you have placed in me. And we will give life to the hope of many in our city. We will succeed as one city."

De Blasio took the ceremonial oath of office from former president Bill Clinton at 1:10 p.m. Former Secretary of State Hillary Clinton was among the VIPs present, along with Gov. Andrew M. Cuomo, whose support de Blasio must win to fulfill a key pledge -- higher income taxes on the rich to pay for universal prekindergarten and after-school programs.

"We do not ask more of the wealthy to punish success. We do it to create more success stories," de Blasio said.

De Blasio also pledged to move quickly to expand a paid sick leave law to cover 300,000 more workers, quickly reform the NYPD's stop-and-frisk practice, require big developers to build more affordable housing and fight hospital closures. "We won't wait. We'll do it now," de Blasio said repeatedly.

Clinton, before administering the oath, embraced de Blasio's call to fight income inequality.
"It is not just a moral outrage," he said. "It is a constraint on economic growth."

Singer, actor and civil rights movement veteran Harry Belafonte, 86, opened the ceremony, saying de Blasio will take on "the naysayers of progress in our midst."

An audience that was expected to number at least 5,000 filed into the plaza in front of City Hall, wearing heavy winter layers and smiles in support of de Blasio. The new mayor -- accompanied by wife Chirlane McCray, son Dante and daughter Chiara -- arrived by subway and shook hands with well-wishers as he emerged and walked to the hall.

The mood was celebratory, with a handful of guests dancing on the left of the stage to a DJ's music. Jackson 5 oldies were among those played.

Democrats were exultant to see one of their own as mayor after 12 years of Michael Bloomberg and eight years of Rudy Giuliani.

Lewis Goldstein, 70, a retired educator from the Bronx, member of the Bronx County Democratic Committee and lifelong liberal, said, "There's a Yiddish word: kvell."

"It's time for a clean break," said Connor Meakey, 29, of Greenpoint, Brooklyn.

Maxine McCrey, 60, of Harlem, an actress and activist, said de Blasio's inauguration means "we need to not put all our energy into the rich."

De Blasio's family has been front and center throughout his campaign and since. Said McCrey: "He is a father figure. Mayor Bloomberg was like an administrator."

Nancy Shamban, 68, of the West Village, said, "The de Blasio family is sort of the epitome of what New York City is."

Many in the audience posed for photos and selfies with each other and with appointees to the de Blasio administration, such as Schools Chancellor Carmen Fariña.

Organizers had set navy blue blankets on some seats to help ward off the cold. Security was tight around City Hall, with police officers and cruisers lining the perimeter. Guests walked through metal detectors and their purses and bags were searched as a safety measure.

"It's a great day," said Councilmember Brad Lander (D-Brooklyn), a longtime de Blasio supporter.

"This is a real celebration of goals for the next four years, which is bringing New Yorkers together and making this a more just, equal and compassionate city."

Fariña said she is feeling "euphoric, because the teachers are happy."

De Blasio officially became mayor minutes after midnight in a private ceremony in front of his Park Slope row house, with State Attorney General Eric T. Schneiderman administering the oath of office.

Comptroller Scott Stringer and Public Advocate Letitia James, who represent the rest of the Democrats' electoral sweep of citywide offices in November, also were ceremonially sworn in at the midday event.

De Blasio, 52, has stoked expectations of a sea change from three-term Mayor Michael Bloomberg. His proposals -- from hiking taxes on the wealthy for funding universal prekindergarten to dropping Bloomberg's appeal of a federal ruling ordering reforms to stop-and-frisk -- aspire to recast a "tale of two cities" according to an egalitarian vision.