WASHINGTON - House Democrats ushered in a new generation of leaders on Wednesday with Rep. Hakeem Jeffries elected to be the first Black American to head a major political party in Congress at a pivotal time as long-serving Speaker Nancy Pelosi and her team step aside next year.

Showing rare party unity after their midterm election losses, the House Democrats moved seamlessly from one history-making leader to another, choosing the 52-year-old New Yorker, who vowed to “get things done” in the new Congress, even after Republicans won control of the chamber. The closed-door vote was unanimous, by acclamation.

“We stand on their collective broad shoulders,” Rep. Jeffries said afterward of Ms. Pelosi and her team.

“The best thing that we can do as a result of the seriousness and solemnity of the moment,” he had said earlier, “is lean in hard and do the best damn job that we can for the people.”

It’s rare that a party that lost the midterm elections would so easily regroup and stands in stark contrast with the upheaval among Republicans, who are struggling to unite around GOP leader Kevin McCarthy as the new House speaker as they prepare to take control when the new Congress convenes in January. Wednesday’s internal Democratic caucus votes of Rep. Jeffries and the other top leaders came without challengers. Cheers broke out in the private meeting, where typically contested party elections unfolded instead like church service, a call-and-response affirming Democrats’ confidence in their choices, some in the room said.

The trio led by Jeffries, who will become the Democratic minority leader in the new Congress, includes 59-year-old Rep. Katherine Clark of Massachusetts as the Democratic whip and 43-year-old Rep. Pete Aguilar of California as caucus chairman. The new team of Democratic leaders is expected to slide into the slots held by Pelosi and her top lieutenants — Majority Leader Steny Hoyer of Maryland and Democratic Whip James Clyburn of South Carolina — as the 80-something leaders make way for the next generation.

But in many ways, the trio has been transitioning in plain sight, as one aide put it — Reps. Jeffries, Clark and Aguilar working with Pelosi’s nod these past several years in lower-rung leadership roles as the first woman to have the speaker’s gavel prepared to step down. Pelosi, of California, has led the House Democrats for the past 20 years, and colleagues late Tuesday granted her the honorific title of “speaker emerita.”

“It an important moment for the caucus — that there’s a new generation of leadership,” said Rep. Chris Pappas, D-N.H., ahead of voting.

Democratic Rep. Cori Bush of Missouri called the leadership election “historic” and a “time for change.”

While Democrats will be relegated to the House minority in the new year for the 118th Congress, they will have a certain amount of leverage because the Republican majority is expected to be so slim and McCarthy’s hold on his party fragile.

The House’s two new potential leaders, Reps. Jeffries and McCarthy, are of the same generation but have almost no real relationship to speak of — in fact, the Democrat is known for leveling political barbs at the Republican from afar, particularly over the GOP’s embrace of former President Donald Trump.

Rep.Jeffries served as a House manager during Trump’s first impeachment.

Rep. Jeffries said Wednesday he will work with Republicans “whenever possible but we will also push back against extremism whenever necessary.”

On the other side of the Capitol, Rep. Jeffries will have a partner in Senate Majority Leader Chuck Schumer as two New Yorkers are poised to helm the Democratic leadership in Congress. They live about a mile (1.6 kilometers) apart in Brooklyn.

“There are going to be a group, in my judgment, of mainstream Republicans who are not going to want to go in the MAGA direction, and Hakeem’s the ideal type guy to work with them,” Schumer said in an interview, referencing Trump’s “Make America Great Again” slogan.

Rep. Clark, elected for the No. 2 spot, extended the invitation to Republicans to work with Democrats on bipartisan projects. “Our door is open for any member from across the aisle who wants to get to work for the American people,” she said.

At the same time Aguilar, the third-ranking member, said Democrats emerged from the narrow midterm election with a mandate: “What we’re fighting against is this MAGA extremism” that has captured the right flank of Trump’s party.