Perez named Ellison as his deputy. Ellison is a progressive representative who has left open the prospect of pushing to impeach Trump.

“We are all in this together,” Perez said, calling on Democrats to fight “the worst president in the history of the United States”.

“We need a chair who can not only take the fight to Donald Trump, he said. “We also need a chair who can lead a turnaround and change the culture of the Democratic Party.”

The race between Perez and Ellison was frequently compared to that of Clinton and Sanders, with Perez being seen as the establishment figure and Ellison as the populist who could more effectively help the party appeal to working-class voters.

He tweeted: “One thing I will say about Rep. Keith Ellison, in his fight to lead the DNC, is that he was the one who predicted early that I would win!”

Unlike in other democracies, the leaders of the United States’ two main political parties wield relatively little influence on policy, with leading Congressional Democrats and Republicans holding far more clout.

But the backstage role is taking on greater significance following Clinton’s surprise defeat, with many looking to the chair to take a strong stand in the media and elsewhere fighting Trump.

Perez will succeed the DNC’s interim chair Donna Brazile, who took over after Representative Debbie Wasserman Schultz was forced from the position last summer when leaked emails showed that members of the organisation, which pledges neutrality in presidential primaries, favoured Clinton over Sanders.

Watch: Democrats elect Tom Perez as new party chair

A third DNC candidate, South Bend, Indiana Mayor Pete Buttigieg – a gay, 35-year-old Rhodes Scholar and military veteran – dropped out of the race before the vote, which was held in Atlanta, Georgia.

Liberal Democrats were quick to pounce on Perez, with progressive group Democracy for America criticising the “incredibly disappointing result”.

Choosing Perez “is another missed opportunity for a Democratic Party desperately trying to regain relevance and proves, once again, how out of touch party insiders are with the grassroots movement currently in the streets, on the phone and at town halls nationwide,” said the group’s chair Jim Dean, an early supporter of Ellison in the race.

But Obama, who cast himself in the 2008 elections as the country’s “great uniter,” called for mending rifts.

“What unites our party is a belief in opportunity – the idea that however you started out, whatever you look like, or whomever you love, America is the place where you can make it if you try,” he said.

“I know that Tom Perez will unite us under that banner of opportunity, and lay the groundwork for a new generation of Democratic leadership for this big, bold, inclusive, dynamic America we love so much.”

Republicans claimed that Perez’s victory is an indication of just how much the Democrats have lost touch with the American people.

Republican National Committee chairwoman Ronna McDaniel said in a statement that “by selecting a DC insider, Democrats only create deeper divisions within their own party by pushing a far left agenda that rejects a majority of their base outside Washington”.

During a debate with several DNC candidates on Wednesday, Perez said Democrats needed to “get back to basics” by making house calls in all 50 states and establishing a year-round organising presence to remind American workers that the Democratic Party represents their values and interests.

“When we lead with our message, our message of economic opportunity, that’s how we win,” he said.

Perez also warned that Democrats must reform their party’s presidential primary system, which he said has created “a crisis of confidence” because of its lack of transparency.

He and other candidates, well aware that Democrats lost ground to Republicans in state house and governor races, stressed the need to seed the party with new, young talent.

Reuters, Agence France-Presse, Business Insider