"I'm going to get you some French fries," Trump told one customer. "I love McDonald's. I love jobs."
As reporters and aides watched, an employee showed Trump how to dunk baskets of fries in oil, salt the fries, and put them into boxes using a scoop. Trump, a well-known fan of fast food and a notorious germophobe, expressed amazement that he didn't have to touch the fries with his hands.
"It requires great expertise, actually, to do it right and to do it fast," Trump said with a grin, putting away his suit jacket and wearing an apron over his shirt and tie.
The visit came as he's tried to counter Democratic nominee Kamala Harris' accounts on the campaign of working at the fast-food chain while in college, an experience that Trump has claimed - without offering evidence - never happened.
A large crowd lined the street outside the restaurant in Feasterville-Trevose, which is part of Bucks County, a key swing voter area north of Philadelphia. Later Sunday, Trump was attending an evening town hall in Lancaster before catching the Pittsburgh Steelers home game against the New York Jets.
After serving bags of takeout to people in the drive-thru lane, Trump leaned out of the window, still wearing the apron, to take questions from the media staged outside. The former president, who has constantly promoted falsehoods about his 2020 election loss, said he would respect the results of next month's vote "if it's a fair election."
He joked about getting one reporter ice cream and when another asked what message had for Harris on her 60th birthday on Sunday, Trump said, "I would say, Happy Birthday, Kamala," adding, "I think I'll get her some flowers."
Trump did not directly answer a question of whether he might support increased minimum wages after seeing McDonald's employees in action but said, "These people work hard. They're great."
He added that, "I just saw something... a process that's beautiful."
When aides finally urged him to wrap things up so he could hit the road to his next event, Trump offered, 'Wasn't that a strange place to do a news conference?'
Trump has long questioned Harris' story of working at McDonald's
Trump has fixated in recent weeks on the summer job Harris said she held in college, working the cash register and making fries at McDonald's while in college. Trump says the vice president has "lied about working" there, but not offered evidence for claiming that.
"When Trump feels desperate, all he knows how to do is lie," Harris campaign spokesman Ian Sams said Sunday. "He can't understand what it's like to have a summer job because he was handed millions on a silver platter, only to blow it."
In an interview last month on MSNBC, the vice president pushed back on Trump's claims, saying she did work at the fast-food chain four decades ago when she was in college.
"Part of the reason I even talk about having worked at McDonald's is because there are people who work at McDonald's in our country who are trying to raise a family," she said. "I worked there as a student."
Harris also said: "I think part of the difference between me and my opponent includes our perspective on the needs of the American people and what our responsibility, then, is to meet those needs."
Trump has long spread groundless claims about his opponents based on their personal history, particularly women and racial minorities.
Before he ran for president, Trump was a leading voice of the "birther" conspiracy that baselessly claimed President Barack Obama was from Africa, was not an American citizen and therefore was ineligible to be president. Trump used it to raise his own political profile, demanding to see Obama's birth certificate and five years after Obama did so, Trump finally admitted that Obama was born in the United States.
During his first run for president, Trump repeated a tabloid's claims that Texas Sen. Ted Cruz's father, who was born in Cuba, had links to President John F. Kennedy's assassin, Lee Harvey Oswald. Cruz and Trump competed for the party's 2016 nomination.
In January of this year, when Trump was facing Nikki Haley, his former U.N. ambassador, in the Republican primary, he shared on his social media network a post with false claims that Haley's parents were not citizens when she was born, therefore making her ineligible to be president.
Haley is the South Carolina-born daughter of Indian immigrants, making her automatically a native-born citizen and meeting the constitutional requirement to run for president.
And Trump has continued to promote baseless claims during this campaign. Trump said during his presidential debate with Harris that immigrants who had settled in Springfield, Ohio, were eating residents' pets - a claim he suggested in an interview Saturday was still true even though he could provide no confirmation.
Trump's visit created a spectacle in Pennsylvania
Police closed the busy streets around the McDonald's during Trump's visit. Authorities cordoned off the restaurant as a crowd a couple blocks long gathered, sometimes 10- to 15-deep, across the street straining to catch a glimpse of Trump. Horns honked and music blared as Trump supporters waved flags, held signs and took pictures.
John Waters, of nearby Fairless Hills, had never been to a Trump rally and had hoped to see the former president so close to his house after missing other nearby rallies.
"When I drove up, all the cars, unbelievable, I was like, 'He's here's, he's coming, he's definitely coming with this all traffic,'" Waters said.
Trump is especially partial to McDonald's Big Macs and Filet-o-Fish sandwiches. He's talked often about how he trusts big chains more than smaller restaurants since they have big reputations to maintain, and the former president's staff often pick up McDonald's and serve it on his plane.
Barrett Marson, a Republican strategist in Arizona, said using a campaign visit to focus on the claims about McDonald's four decades ago is a "puzzling detour," but that Trump is "not above throwing anything on the wall to see if it sticks."
"When Donald Trump isn't talking about the economy and illegal immigration, he's off topic about the things that people care about," Marson said.
Sunday marks big day for campaigning around Philadelphia area
While Trump was manning the fry station, Republican Representative Bryon Donalds from Florida spoke with dozens of Black men -- ranging from business owners to nonprofit leaders -- at a barber shop in Philadelphia's Kensington section.
At the On Point Hair Studio, community members spoke about the problems they face within the city and potential solutions if Trump was elected.
"It was very powerful, intellectual, well-needed. A blessing. It was full circle for me," said Shawn Banks from North Philadelphia.
"I never thought one day, in time I would be sitting in a Trump meeting and having a conversation with people affiliated with this candidate. But I had to come down here as a Black man and see what's really going on with this election and not just because Kamala is a woman and Black woman. I need to know if the right person is going to get in there right now, because right now, this is going to change America," he added.
Donalds told voters that Trump is advocating for positive change.
"His mission is not just about the country's wealth overall. It's about everybody being a part of this American dream, no matter who they are," said Donalds.
"I think he's better because it will be a more business-direct dialogue conversation. I feel like we'll be more precise to get a return on investments," said Robert Williams from North Philadelphia, who says he is now voting Republican.
Early on Sunday, Philadelphia Mayor Cherelle Parker and state Senator Jimmy Dillion made their way across Northeast Philadelphia to encourage people to vote for Harris.
"It's so important to get people enthused and energetic heading into November 5 so we have a great turnout for our city and have everybody's voices heard at the polling places," said Dillion.
Parker also campaigned at a labor rally with local and federal leaders.
New York Congresswoman Alexandria Ocasio-Cortez and the United Auto Workers President held that rally in Northern Liberties.
There, they blasted Trump's McDonald's campaign stop and his agenda for unions.
"He puts on a costume but doesn't actually fight for the people who wear the uniform and I think it's a shame and Pennsylvanians deserve better," said Ocasio-Cortez. "He doesn't advocate for raising the minimum wage for McDonald's workers."
While Harris campaigned in Georgia over the weekend, she is expected to travel on her birthday to Philadelphia. She, along with former U.S. Representative Liz Cheney, is set to stop in Chester County on Monday as Election Day draws closer.
The Associated Press contributed to this report.