Trump met with boos and chants while selling sneakers in Philadelphia

The day after a New York judge fined him $355 million in the wake of a lengthy fraud trial, which he plans to appeal, former President Donald Trump spent his Saturday in two battleground states, Pennsylvania and Michigan.

First stop: Sneaker Con in Philadelphia.

"Sneakerheads, you're sneakerheads, right? Does everybody in the room consider themselves a sneakerhead?" Trump said in a short speech to an unusual crowd that was divided between chanting for and booing at him.

The event was supposed to be part of an unveiling of the latest Trump merchandise: gold "Never Surrender" high-top sneakers selling for $399, which are already listed as sold-out online, and "Victory47" fragrances for $99. (Also available: "Red Wave" and $199 "POTUS 45" shoes.)

Trump himself took the stage holding a pair of the high-top sneakers.

But his five-minute remarks, in a heavily Democratic city, were sometimes barely able to be heard as members of the diverse, young crowd were consistently screaming and chanting throughout.

While many booed and chanted at him, others attempted to drown them out with anti-Joe Biden and USA chants.

"This a slightly different audience than I'm used to, but I love this audience," Trump said, struggling to get through his speech.

He attempted to divert the attention by acknowledging his supporters in the crowd, even bringing one of them, a woman, up to the stage where she talked about how much she loves Trump because she said he is a Christian family man.

"They're after him for no reason. Go out and vote for Trump," she said to boos and some cheers.

Trump even acknowledged he wasn't necessarily in friendly territory -- "Right after this, I go to Michigan ... I'll be talking about a slightly different subject than sneakers. But you know what? It's all part of Americana," he said.

That didn't stop him from making his pitch in Philadelphia.

"What's the most important thing: to go out and vote, right? We have to go out and vote. We got to get young people out to vote," he said.

Later, in Michigan, an angry Trump came out swinging, railing against all the prosecutors investigating him. He faces 91 criminal charges, all of which he denies.

He told the fired-up crowd that if he wins the swing state, which will likely be a key battleground, then he will win the entire election.

However, he also misstated the upcoming Republican primary date and gave the wrong year for when he won Michigan -- gaffes that critics like primary rival Nikki Haley have seized on to argue that he is "diminished."

Trump has attacked President Joe Biden for similar slips but defended his own mental acuity. "I feel my mind is stronger now than it was 25 years ago," he said in January.

The former president returned to the campaign trail this weekend in the wake of perhaps his biggest legal setback to date, when the judgment came down at the end of a yearslong civil fraud lawsuit in New York.

With a 92-page order issued late Friday, Judge Arthur Engoron dealt Trump a legal and financial blow that could permanently damage the business empire that propelled him to the presidency.

In addition to the nine-figure penalty, Engoron temporarily stripped Trump and his sons of the ability to lead their own businesses or apply for financing.

Trump's lawyers plan to appeal the ruling, vowing that higher courts will reverse Engoron's ruling.

ABC News' Peter Charalambous contributed to this report.