House Democrats on Wednesday elected the New York congressman Hakeem Jeffries as their new leader, making him the first Black American to lead a major political party in Congress after Nancy Pelosi, the current speaker, announced that she was stepping aside to pave the way for a new generation.

Jeffries, 52, will assume the role of minority leader when the new Congress is sworn in early next year, inheriting the position held for nearly two decades by Pelosi, a towering figure in Democratic politics who was the first woman speaker.

In a show of unity after losing the House but delivering a stronger-than-expected performance in the midterm elections, Democrats unanimously approved Jeffries and two other top leadership positions by acclamation.

Emerging from the closed-door meeting room, the soon-to-be leader declared: “House Democrats fight for the people. That’s our story. That’s our legacy. That’s our values. That’s our commitment.”

The trio of top leaders led by Jeffries will include the Massachusetts congresswoman Katherine Clark, 59, as whip and Pete Aguilar of California, 43, as caucus chair, in charge of messaging. They will take the mantle from three octogenarians: Pelosi and her long-serving deputies, Steny Hoyer of Maryland (majority leader) and James Clyburn, the whip from South Carolina.

“Today is a day of transition and hope and a renewal of the shared values of our caucus,” Clark told reporters.

Hailing the Democratic caucus as a “beautiful mosaic of the country”, Aguilar acknowledged the significance of being a Latino in a leadership role.

“Having an opportunity to help guide this caucus is a great responsibility and I don’t take it lightly,” he said.

The seamless elevation of a new generation of leaders came in stark contrast to the fractured House Republican conference, which has yet to unite around Kevin McCarthy after the weaker-than-expected midterms win. With only a few votes to spare, McCarthy is attempting to shore up enough support to become speaker.

The narrow margin of Republicans’ majority, and McCarthy’s tenuous hold on his caucus, is likely to give Democrats some leverage in negotiations, particularly when it comes to must-pass legislation. Vowing to “get stuff done”, Jeffries said his caucus would look for opportunities to work with Republicans but would “push back against extremism whenever necessary”.

Shortly before Thanksgiving, Pelosi, who has led Democrats since 2003, announced that she intended to pass the torch and would support Jeffries, another barrier-breaking leader.

On Tuesday, House Democrats granted Pelosi the honorific title of “speaker emerita”. Clyburn, now the highest-ranking Black member of Congress, intends to remain as assistant leader to help with the transition. That election, and votes for other leadership posts, will take place on Thursday.

Jeffries is a former lawyer who represents a diverse district in Brooklyn and Queens once represented by Shirley Chisholm, the first Black woman to serve in Congress. He is known on Capitol Hill as a disciplined tactician with a measured style and a penchant for pop culture references.

In remarks to reporters on Wednesday, Jeffries traced his ascent from the Brooklyn hospital where he was born, the son of a caseworker and a social worker. Moved by what he described as a desire to “advance the ball for everyday Americans”, he first won election to the New York state assembly, where he sat for six years.

Some progressives view Jeffries skeptically as a business-friendly centrist but such concerns were not raised on Wednesday. The vote was a jovial affair, celebrated with “handshakes, high fives and hugs”, Aguilar said.

Pramila Jayapal of Washington state, chair of the Congressional Progressive Caucus, said: “With this new generation of leadership, House Democrats are well positioned to enter the 118th Congress and confront the challenges ahead.”

Jayapal also noted that House Democrats’ top three leaders would for the first time be entirely “women or people of color”.

In his own statement, Hoyer called Jeffries “a skilled consensus-builder, effective legislator, and experienced leader … well equipped to … deliver further results for the people during the 118th Congress and retake the majority in 2024.”

Though Pelosi will remain in Congress, she promised not to be the “mother-in-law in the kitchen”. Asked if the continued presence of Pelosi, Hoyer and Clyburn might be a burden, Jeffries said the new leaders felt honored to “stand on their shoulders”.

“It’s a blessing that we embrace,” he said.