Kim Janey is making history in Boston as the first woman and Black person to serve in the city’s highest office.

Marty Walsh resigned to become President Joe Biden’s labor secretary. Janey, who served as Boston’s City Council president, stepped into the role of acting mayor and was ceremonially sworn in on Wednesday.

Walsh says he welcomes the change in ethnicity in Boston’s mayor’s office. “History will be made tonight,” Walsh said.

 “We’re an extremely diverse city from different backgrounds and different nationalities and different skin colours. I think it’s a good thing for our city. I think it’s a great thing for our city.”

Janey, via Twitter, congratulated Walsh on his new position in the Biden Administration.

 “Congratulations on your confirmation, Secretary Walsh. You are a proud son of Dorchester who will bring our city with you,” the fellow Democrat tweeted. “The working people of America will benefit greatly from your passion.”

She added: “Now, we look ahead to a new day — a new chapter — in Boston’s history.”

Janey and Walsh have reportedly had regular meetings and extensive planning sessions over the past two months.

“Together the council president and myself and our teams have worked diligently to ensure a smooth transition,” he said.

Janey has experienced a very quick ascension in Boston politics. She was sworn in as city councillor just three years ago and is now serving a role, albeit on an interim basis, that has previously been filled by Irish-American and Italian-American men.

Two of the city’s most prominent Black women participated in the ceremony. Congresswoman Ayanna Pressley, Boston’s first woman of color to serve on the council, was in attendance and Supreme Judicial Court Chief Justice Kimberly Budd, the first Black woman to hold that title in Massachusetts, administered Janey’s oath of office. Janey’s six-year-old granddaughter stood by her side.

The Roxbury native has not yet announced whether she will run in the mayoral election this fall.