‘We have so much work to do.’ Michelle Wu sworn in as mayor of Boston

Michelle Wu stood with her family as she was sworn into office at City Hall on Tuesday.Jessica Rinaldi/Globe Staff

In perhaps the most significant transfer of power in the city’s modern history, Michelle Wu on Tuesday was sworn in as Boston’s first woman, first person of color, and first Asian American mayor popularly elected to office.

She kicked off her historic tenure declaring, “We have so much work to do.”

When Wu finished taking the oath of office at 12:34 p.m., the crowd, packed with local pols in the Iannella Chamber on City Hall’s fifth floor, broke into cheers and applause, as did the overflow throng outside the room.

“The first time I set foot in City Hall, I felt invisible, but today I see what’s possible in this building,” Wu told those gathered.

She vowed to get “City Hall out of City Hall” and into the neighborhoods and said her administration’s charge is to “fight urgently for our future.”

“Not only is it possible for Boston to deliver basic city services and generational change, it is absolutely necessary in this moment to tackle our biggest challenges by getting the small things right,” she said.

Her speech served as a political victory lap of sorts for Wu, who recalled her past successes on the council, including helping deliver paid parental leave, housing protections, and language access.

She remembered landing an internship in Thomas M. Menino’s administration, but added that it was on the chamber’s floor, where the City Council meets and where she has served for the past seven-plus years, that she learned the ropes of city politics, a nod to her choice of venue for the swearing-in.

The festive ceremony, more yeoman-like than the celebrations that have marked the start of past mayoral administrations, was attended by many local political luminaries, including outgoing Acting Mayor Kim Janey; Representative Ayanna Pressley, with whom Wu served on the City Council for multiple terms; Governor Charlie Baker; and Senators Elizabeth Warren and Edward J. Markey. Numerous attendees sported clothing in shades of Wu’s signature purple, including Warren and Wu’s husband, Conor Pewarski, who wore a purple tie.

One notable absence: former mayor and Wu political rival Martin J. Walsh, who left City Hall earlier this year to become the nation’s secretary of labor. Wu and Walsh had clashed at times during his tenure, and Wu announced she would be running for mayor before it was known Walsh would be leaving for Washington, D.C.

Before Wu’s swearing-in, Janey — the first woman and person of color to serve in the role of mayor, though in an acting capacity — alluded in her remarks to the decades-long struggle for racial equity in Boston.

“This new day has been dawning for a while, and so many people have helped to usher it in,” Janey said, referencing Mel King’s historic mayoral candidacy in the 1980s, as well as Pressley’s ascension to the council before becoming a US representative.

“I am so proud to call you Madam Mayor,” Janey said.

The event offered plenty of other symbolic gestures about the dramatic difference Wu’s victory means for a city with a hard-earned reputation for resisting change. Wu took the oath with her left hand on the city-owned Aitken Bible, the earliest complete English-language Bible printed in the United States, which her sons — Blaise, 6, and Cass, 4 — jostled to help hold for her.

And Wu made clear her choice of venue was deliberate, not only as the place she cut her political teeth. She noted that when she was first elected to the council, the chamber was not accessible to everyone. The floor, she said, used to be in a pit three steps down, which prevented Bostonians in wheelchairs and with mobility challenges from coming down directly to testify on the floor and advocate for change. But as council president, Wu was central to an effort to reshape the room, bringing the floor up.

“When we make City Hall more accessible, we are all raised up,” she said.

Speaking to reporters after the ceremony, Wu, a Harvard-educated attorney, was peppered with questions about topics ranging from development to the city’s opioid crisis to policing.

“The beauty of city government is that we do the big and the small,” she said.

Stable, supportive, accessible housing, Wu said, is the number one need right now to alleviate the humanitarian crisis in the area known as Mass. and Cass, which is the heart of the city’s opioid crisis.

Additionally, this week marked the first time Wu’s team has met with the Boston Planning & Development Organization, an agency Wu has publicly proposed abolishing in the past. She said she was looking to appoint leaders who would address immediate development needs in the city while also implementing larger structural reforms to city planning.

Regarding her promised national search for the next police commissioner, she said a group of individuals will first seek community input before vetting candidates.

“We’ll be announcing details of that soon,” she said.

Wu, a 36-year-old Roslindale resident, defeated her City Council colleague, Annissa Essaibi George, in the general election.

“This is a great day in our city’s nearly 400-year history,” City Councilor Matt O’Malley said during the ceremony.

Ahead of the swearing-in, Wu announced a slew of appointments, including Mary Lou Akai-Ferguson, who served as Wu’s campaign manager during the mayoral race, to serve as her interim chief of staff.

The start of Wu’s tenure caps an eventful year in city politics; she is the third mayor in 2021, and she emerged from a historically diverse mayoral field. Walsh became labor secretary in the Biden administration in March, and Janey, as City Council president, became acting mayor in his absence and was eliminated from the mayor’s race in September.

Due to Walsh’s departure, Tuesday’s swearing-in was an unusually quick turnaround from Election Day, coming just two weeks after Wu won. (Typically, a new Boston mayor takes office in early January.)

Wu captured a new coalition in Boston, breaking with a decades-long trend of winning City Hall by dominating parts of Dorchester, South Boston, West Roxbury, and Hyde Park.

Her victory was not close: Polls had predicted she would defeat Essaibi George in a landslide of more than 30 points, and her actual vote share came in around 28 points higher than Essaibi George’s. During her campaign, Wu presented an unapologetic, progressive agenda that included an entirely new approach to downtown development and a municipal-level Green New Deal, and unabashed advocacy for equitable public transit options, among a slew of other proposals.

A millennial, Wu is the youngest mayor leading one of the nation’s 25 largest cities.

“My generation has grown up with comfort with discomfort, a comfort with disruption,” Wu told reporters.

She will be the city’s first mayor in over a century who was not born and raised in Boston. With her two young sons, she is also the first mother elected to lead City Hall.

Wu is the sixth Asian American woman to serve as mayor in any of the country’s 100 largest cities, according to the Center for American Women and Politics at Rutgers University.

And during her speech, Wu indicated she wanted to waste no time in getting down to the business of governing.

“Let’s get to work,” she said.

Travis Andersen of the Globe staff contributed to this report.