The 81-year-old US president even visited his childhood home in the former mining town as he contrasted his blue-collar roots with the election rival he branded a self-obsessed billionaire.
In a speech calling for the wealthy to pay more taxes, Biden said he "learned a lot here in Scranton."
"I learned that money doesn't determine your worth."
"People like Donald Trump learned very different lessons... he learned that telling people 'you're fired' is something to laugh about," he added, referring to Trump's catchphrase on the reality TV show "The Apprentice."
Democrat Biden made no reference to Trump's historic hush money trial in New York, which is keeping the Republican off the campaign trail.
But he repeatedly drew broader contrasts with Trump, saying November's vote was a battle between "Scranton values or Mar-a-Lago values," in a reference to Trump's luxury Florida mansion.
"Donald Trump looks at the world differently to you and me," a fired-up Biden said.
"He wakes up in the morning in Mar-a-Lago thinking about himself, how he can help his billionaire friends gain power and control and force their extreme agenda on the rest of us."
The Scranton visit kicks off a three-day swing through Pennsylvania, a key swing state Biden narrowly carried in the 2020 election against Trump.
Also known as the setting for the US version of hit TV comedy "The Office," Scranton has long been at the heart of the political mythology Biden has cultivated about his hardscrabble upbringing there.
During his visit he drove down an expressway named in his honor and visited his wood-paneled childhood house, where large crowds including school children were cheering.
There were also some Palestinian flags flying, as protests continue against Biden's support of Israel's war in Gaza.
- 'Bloodbath' -
Biden's campaign earlier released a social media ad featuring Scranton locals, including a cousin, bashing Trump as rich and selfish.
His homecoming trip rides on recent momentum in polls that show him catching up with Trump, after months of trailing the Republican.
Biden meanwhile mocked Trump for his recent fundraising advantage over his rival, quipping that if stock in Trump's media group "drops any lower, he might do better under my tax plan than his."
On a more serious note Biden angrily attacked Trump as a threat to democracy, returning to a theme Democrats hope will resonate with voters.
"He says he'll be a dictator on day one, he promises a bloodbath if he loses, this guy denies January 6," added Biden referring to the 2021 attack on the Capitol by Trump supporters after his election loss.
Biden however made no mention of the trial occupying Trump's time this week.
The Republican himself angrily complained outside the Manhattan courtroom on Tuesday that he "should be right now in Pennsylvania and Florida -- in many other states, North Carolina, Georgia -- campaigning."
The White House said Biden would not be following the proceedings in New York.
"His focus is on the American people," Press Secretary Karine Jean-Pierre told reporters traveling with the president aboard Air Force One.
Voters in Scranton said they were worried about a range of issues ahead of November's election.
Trump "is talking about eliminating taxes so I would lose my job," said Rose Williams, 41, a tax professional from Scranton.
"When I go to vote, I'll be voting for Biden."
But she added that she was concerned about issues such as poverty and also Biden's support for Israel's war on Hamas in Gaza.
"I just prefer Biden," added Debra Hodges, 66, who does volunteer work and moved to the town from New York City about 20 years ago.
"His age is not a problem for me. I mean, we're all going to get older," she said, referring to another poll worry for Biden.
