Trump was met with loud boos as well as cheers at the Philadelphia Convention Center as he introduced what he called the first official Trump footwear.
The shoes, gold lame high tops with an American flag detail on the back, are being sold as "Never Surrender High-Tops" for $US399 ($A612) on a new website that also sells Trump-branded "Victory47" cologne and perfume for $US99 ($A152) a bottle.
He'd be the 47th president if elected again.
The website says it has no connection to his campaign, though Trump campaign officials promoted the appearance in online posts.
On Friday, a judge in New York ordered Trump to pay a whopping $US355 million ($A545 million) in penalties, finding the former president lied about his wealth for years, scheming to dupe banks, insurers and others by inflating his wealth on financial statements.
That penalty came after Trump was ordered to pay $US83.3 million to the writer E. Jean Carroll for damaging her reputation after she accused him of sexual assault.
With interest payments, Trump's legal debts might now exceed a half-billion dollars - an amount it is unclear he can afford to pay.
Trump's appearance was met with clashing boos from his detractors and chants of "USA!" from supporters who arrived at the sneaker event decked out in Trump gear.
The duelling chants made it difficult, at times, to hear Trump speak. Some held signs that read "SNEAKERHEADS LOVE TRUMP".
"There's a lot of emotion in this room," Trump said of the reaction, after holding up and showing off a pair of gold shoes, then placing one on each side of his podium.
"This is something that I've been talking about for 12 years, 13 years," he said.
Some of those who attended said they were unaware Trump would be there, and continued to shop as a crowd gathered around the stage.
The attendees skewed younger and more diverse than Trump's usual rally crowds.
Trump's campaign is hoping he will be able to win over more young and minority voters, particularly young Black men, in a likely rematch against President Joe Biden in November.
This isn't the first money-making venture Trump has announced since launching his third campaign for the White House in 2022.
Trump last year reported making between $US100,000 and $US1 million for a series of digital trading cards that portrayed him, through photo editing, in a series of cartoon-like images, including an astronaut, a cowboy and a superhero.
Trump's new sneaker website states the new venture "is not political and has nothing to do with any political campaign".
The website describes the shoes as a limited-edition, numbered "true collector's item" that is "Bold, gold, and tough, just like President Trump."
"The Never Surrender sneakers are your rally cry in shoe form," the description reads. "Lace-up and step out ready to conquer."
