The pair of appearances come after Biden joined a Saturday call with campaign surrogates, and reiterated that he has no plans to step aside, while urging unity among top Democrats.
But he also listened to concerns and feedback, according to two people who spoke on condition of anonymity to discuss private conversations.
The president pledged on the call to campaign harder going forward and to hit the road more frequently, taking his message to voters more directly.
He's getting the chance at a church service at Mount Airy Church of God in Christ in northwest Philadelphia, then going to the state capital of Harrisburg to speak at an event with union members and local Democrats.
US President Joe Biden says only the "Lord Almighty" could convince him to end his re-election bid. (AP PHOTO)
On Sunday evening, Biden returns to Washington, where leaders from NATO countries will gather for a three-day summit beginning Tuesday to mark the military alliance's 75th anniversary.
The focus could shift more to Russia's war in Ukraine than questions about Biden's re-election campaign, but the 81-year-old Biden's political situation remains precarious.
Five Democratic lawmakers have called on him to abandon his re-election bid ahead of November, and more could do so in coming days, as Congress reconvenes.
Meeting in person will give congressional Democrats a chance to discuss concerns about Biden's ability to withstand the remaining four months of the campaign — not to mention four more years in the White House — and true prospects of beating former Republican former President Donald Trump.
The president's campaign has announced a $US50 million ($A74 million) ad blitz throughout the month meant to target large-audience moments like during the upcoming Olympics in Paris.
Still, Biden's campaign team is quietly bracing for the chorus of those calling for him to leave the race to grow in coming days — holding the call with surrogates and calling and texting lawmakers to try and head off more potential defections.
Biden got a weekend boost from other key Democrats who had raised previous questions but now have moved to support him, led by Speaker Nancy Pelosi and Representative James Clyburn of South Carolina.
Still, with the Democratic convention approaching, the short term is especially critical.
Since his disastrous debate performance late last month donors, strategists, lawmakers and their constituents have urged Democrats to replace him at the top of the ticket before, they argue, it's too late.
Biden's Friday interview with ABC has not convinced some who remain sceptical that he can resurrect his campaign.
Appearing on CNN on Sunday, Democratic Senator Chris Murphy of Connecticut said that Biden "needs to answer those questions that voters have".
But he added: "If he does that this week, I think he will be in a very good position and we can get back to what this campaign needs to be".
Murphy also said he didn't know if a cognitive test "would be impactful" for voters worried about Biden's potential decline.
During his Friday interview, Biden rejected undergoing such testing, arguing that the everyday rigours of the presidency were proof enough of his mental acuity.
But California Democratic Representative Adam Schiff told NBC that he'd be "happy if both the president and Donald Trump took a cognitive test."
Trump, during his own campaign rallies, has said Biden should undergo such testing while boasting about his own mental and physical stamina.
