Bill de Blasio, the first Democrat in more than two decades, has been sworn in as the new mayor of New York City.
Bill de Blasio took the oath of office outside his home a few minutes into the New Year, in line with tradition.
A grander inauguration ceremony will take place later at City Hall, with former President Bill Clinton administering the oath of office.
Bill de Blasio succeeds billionaire Michael Bloomberg, and has promised to govern with a liberal agenda.
He won November’s election by a record margin, contrasting himself with the pro-business Bloomberg years which he said had created a “tale of two cities”.
Michael Bloomberg is credited with leaving New York a safer, healthier and revitalized place after his 12 years in office. However, critics say his policies have widened the gap between rich and poor.
Bill de Blasio, 52, was joined by his wife Chirlane McCray and their two teenage children outside their home in Brooklyn for the oath of office administered by state attorney Eric Schneiderman.
“To everyone, this is the beginning of a road we will travel together,” he said after he was sworn in.
He is New York’s first Democratic mayor since David Dinkins, who became the city’s first black leader in 1993.
Bill de Blasio has promised to reverse the city’s rising income inequality and end a controversial stop-and-frisk policy which has been criticized for disproportionately targeting black and Hispanic men.
He worked as an aide to David Dinkins when he was mayor and has also worked closely with the Clintons, managing Hillary Clinton’s successful 2000 run for the US Senate.
He was elected to New York City Council in 2001, representing his home area of Brooklyn, before becoming public advocate, the city’s official watchdog.
Bill de Blasio’s bid for the mayor’s job was aided by the implosion of the campaign of former congressman Anthony Weiner.