President Joe Biden used his valedictory address at the Democratic National Convention on Monday to deliver a lengthy defence of his own record aimed at cementing a 50-year legacy of public service, even as he passed the reins to Vice- President Kamala Harris as the new face of the party he led until just weeks ago.

Speaking to a raucous arena filled with Democrats who chanted “We Love Joe!” and gave him a three-and-a-half-minute standing ovation, Biden grew emotional as he delivered what amounted to a political farewell to his most fervent supporters.

“I’ve given my heart and soul to our nation, and I’ve been blessed a million times in return,” the president said as he made the case that Harris is the best person to lead the country now that he is no longer in the race.

“She’s tough. She’s experienced. And she has enormous integrity,” Biden said. Selecting Harris as his vice-president, he added, “was the best decision I made my whole career”.

That was not the case that Biden expected to be making just over a month ago, before his stunning political demise following a debate performance that raised doubts about his age and vitality. And in some ways, his praise of Harris during the 52-minute address seemed secondary to his desire to recount the greatest hits of his career in a speech he might have given as the party’s nominee.

One by one, Biden ticked through a litany of achievements from the stump speeches of his now-ended campaign: $35 insulin; breathing room for American families; strengthening NATO; beating “big Pharma”; burn pits that harmed veterans; investments in infrastructure; appointing a Black woman to serve on the Supreme Court; and the now-familiar call to remember “who the hell we are: We’re the United States of America, and there’s nothing we can’t do if we do it together”.

And he recited a favourite phrase from American Anthem, a song of modern politics sung by the mezzo-soprano Denyce Graves for Presidents of both parties. “America, I gave my best to you,” he said, repeating a line he used during his inaugural address nearly four years earlier.

Describing his one-term presidency as a successful rescue of a country reeling from a pandemic and suffering from the effect of political violence, Biden denounced former President Donald J. Trump, the 2024 Republican nominee, as not worthy of serving in the White House during his first term — “not then, not now, not ever”.

Showing flashes of anger, Biden accused Trump of “giving oxygen to the oldest forces that had long sought to tear apart America”, recalling the praise that the former President offered after neo-Nazis marched in Charlottesville, Virginia, in 2017. Biden claimed credit for preventing Trump’s re-election in 2020.

“Democracy has prevailed, democracy has delivered and democracy must be preserved,” the president declared, speaking with a booming voice that echoed throughout the Chicago arena where Democrats gathered to nominate Harris in his place.

Biden took the stage at the convention after an introduction by Ashley Biden, his daughter, who described him as “the OG girl dad”. Biden wiped tears from his eyes as he approached the lectern.

In his remarks on Monday, he vowed to work for Harris’s election and urged Americans to do the same, describing the Democratic ticket of the vice-president and governor Tim Walz of Minnesota as fully committed to the ideals that he embraced as a senator, vice president and president.