"This oath reflects my deep commitment to our great city — and the individuals who are ranked as New York’s Finest," Sewell, 49, tweeted after the ceremony at police headquarters. "I’m privileged to be here and ready to work!"
Sewell became the 45th commissioner of the country’s largest police force after having been chief of detectives in the Nassau County Police Department, where she was based for 25 years.
She chose Edward Caban, a former commanding officer of the Harlem district, to be her second-in-command.
Sewell was selected by New York's new mayor, Eric Adams, who was also sworn into office Saturday in Times Square.
Placing one hand on a family Bible, he held a picture of his mother, Dorothy, who died in 2020, in the other as Associate Justice Sylvia O. Hinds-Radix of the state Supreme Court’s appellate division swore him in.
Adams, 61, a former police captain himself, spoke out against crime, policing and racial injustice on the campaign trail. He also promised to choose a female police commissioner.
He is the city’s second Black mayor, after David Dinkins, who served from 1990 to 1993, and the 110th mayor of New York City.
Both Sewell and Adams will have to grapple with an increase in gun and violent crime.
“We want to do gun interdiction, we want to do anti-gun units, we want to do all sorts of things we can use to stop the violence in the city,” Sewell told NBC New York after her new role was announced last month.
New York City is also grappling with an influx of new infections with the omicron variant of the coronavirus. Adams has said he is considering extending the city's strict vaccination mandate to public schools and is committed to keeping schools open and avoiding any further shutdowns in the city of 8.8 million.
An unconventional politician, Adams has written a book about the benefits of veganism, which said it helped him with diabetes. He has also shown off his favorite smoothie recipe on social media.
He has also been known to frequent some of the city’s nightclubs, saying during an appearance on Stephen Colbert’s late-night show: “This is a city of nightlife. I must test the product. I have to be out.”