The intervention comes as Republicans are predicted to make broad gains on November 8, with forecasters saying they will probably take both the Senate and the House of Representatives, leaving two years on Mr Biden's clock during which he will be unable to enact any significant legislation.
Mr Obama, who was president from 2009-2017, remains a popular figure in the Democratic Party. He is viewed favourably by 53.8 per cent of registered voters and 90.2 per cent of Democrats, YouGov polling data shows.
Mr Biden's approval, meanwhile, remains stuck in the low-40s.
After initially keeping a relatively low profile in the run-up to the midterms, Mr Obama has burst on to the campaign trail in recent days, rallying in the battleground states of Wisconsin, Georgia, Michigan, Iowa, Arizona and Nevada.
In Wisconsin, where Mr Biden very narrowly won in 2020, Mr Obama attacked Ron Johnson, a Republican senator, for his embrace of Donald Trump and his response to the January 6, 2021, attack on the Capitol.
Mr Johnson “has done more than just about anybody in Congress, to spread conspiracy theories about the 2020 election,” Mr Obama said. “I mean he has a gold medal in that event … If that doesn't elicit uniform outrage, what will? What does it take?”
Mr Obama's rhetorical flourishes and his ability to deliver a message contrast with the oratorical skills of Mr Biden, his former vice president, who has struggled to speak coherently at events or rouse the Democratic base.
The gaffe-prone president this week mixed up the war in Ukraine with the war in Iraq and has watched as his Democratic Party has been unable to deliver a unified message at a time when vote-losing issues such as record-high inflation are front and centre for voters.
Mr Biden, who turns 80 this month, is scheduled to make a joint appearance with Mr Obama during a rally in Pennsylvania for US Senate candidate John Fetterman.
On Wednesday, Mr Obama was heckled at an Arizona rally and ended up in a heated exchange.
As he was campaigning for Democratic candidates, he argued that Republicans are working to create an economy that only works for the elite when he was interrupted.
“Like you, Obama,” the heckler shouted.
Mr Obama replied, “Are you going … to start yelling?” as the crowd inside the Phoenix gymnasium began booing the heckler.
“Hey, young man. Young man, just listen for a second. You know, you have to be polite and civil when people are talking … and then you get a chance to talk.”
The former president then told the heckler to “set up your own rally”.
Video shared on Twitter showed the man later being escorted out of the rally.
Mr Obama then shifted to address how that moment was similar to loud voices shutting down moderate arguments in political debates.
“This is what happens in our politics these days. We get distracted. We get one person yelling, suddenly everyone's yelling. You get one tweet that's stupid, suddenly everyone's obsessed with the tweet.”
The former president was rallying for incumbent Democratic senator Mark Kelly and gubernatorial candidate Katie Hobbs, who both face challenging races against their Republican opponents.
Mr Obama also pointed out how the attack on Paul Pelosi, husband of House Speaker Nancy Pelosi, symbolised the growing danger of extreme partisanship in US politics.
“One thing is clear, and that is this increasing habit of demonising opponents,” Mr Obama said.
His remarks mirrored those of Mr Biden, who warned of a “cycle of anger, hate, vitriol and even violence” while speaking during a fundraising event in Washington.