Former US president Barack Obama has endorsed Joe Biden, giving the presumptive Democratic presidential nominee a boost from the party’s biggest fundraiser and one of its most popular figures.

“I believe Joe has all the qualities we need in a president right now,” Mr Obama said in a nearly 12-minute video, touting him as a “close friend” and lauding him for his perseverance and compassion.

The two men are close friends from their two terms in the White House, when Mr Biden served as vice president.

He leaned heavily on his affiliation with the former president throughout the Democratic primary, framing his pitch as an extension of Mr Obama’s presidency. In recent weeks, he has told donors he has been in touch with Mr Obama about his vice-presidential pick.

The endorsement marks Mr Obama’s return to presidential politics more than three years after leaving the White House. He rarely talks directly about his successor, Donald Trump, and avoided intervening in the Democratic primary.

The field at one point spanned nearly two dozen candidates and Mr Obama offered private counsel to anyone who asked for it, but he made no efforts to bolster an individual campaign — including Mr Biden’s.

But Mr Obama has been following the Democratic race closely from the sidelines and is eager to take a more active public role in the campaign. He is expected to headline fundraisers for Mr Biden and public events in key swing states, if those events can still be held given social distancing guidelines during the pandemic.

An Obama adviser said the former president is taking his cues from Mr Biden’s campaign on how he can be most useful as he eases back into a more overtly political role.

Joe Biden with Bernie Sanders
Joe Biden with Bernie Sanders (Evan Vucci/AP)

The endorsement comes a day after Bernie Sanders also backed Mr Biden. The former vice president now has the support of all of his former Democratic primary rivals except for Elizabeth Warren. The Massachusetts senator is expected to formally throw her support behind him soon, according to source.

Two other prominent Democrats who have yet to formally endorse Mr Biden are former president Bill Clinton and Hillary Clinton, the party’s 2016 nominee. Mrs Clinton has been in regular touch with Mr Biden, including several times since Mr Sanders dropped out of the race, according to an aide.

Mr Obama has been an obvious shadow throughout the 2020 Democratic primary. Mr Biden coined the “Obama-Biden administration” moniker when he spoke about various accomplishments.

But he also tried to insist he was running as his own man, saying he urged Mr Obama not to endorse him straight away or even in the thick of the primary.

Mr Biden leaned even more heavily into Mr Obama as primary voting began. Aiming at Mr Sanders, the self-described “democratic socialist”, and billionaire Mike Bloomberg, who had been elected New York City mayor as a Republican, Mr Biden said “they’re not bad folks. They’re just not Democrats”.