Chief Anchor George Stephanopoulos anchored the event, titled "The President and the People."
The forum provided uncommitted voters the opportunity to ask the president their questions on issues affecting Americans-- from the coronavirus pandemic and economic recovery to protests for racial justice and climate change. The guests, selected by ABC, came from a wide background. Some previously voted for Trump, others did not.
The first and most discussed topic was about coronavirus. Trump, to no surprise, defended his administration's response.
"It came off from China. They should have never let it happen. And if you look at what we're doing with ventilators and now vaccines, were very close to having vaccine," said Trump.
The president also answered questions about comments he made to journalist Bob Woodward about downplaying the coronavirus.
FACT CHECK: President Trump town hall fact check: What's true and what's false?
Trump says he didn't downplay the coronavirus pandemic, even though he told Woodward that he did so intentionally.
Trump told Woodward that he always wanted to "play it down" because he didn't want people to panic. He also called the virus "deadly stuff." Trump's comments were captured on a recording Woodward made for his latest book, "Rage," which was published Tuesday.
READ MORE: President Trump may have knowingly downplayed coronavirus risks, according to new Bob Woodward book
Three days after delivering his "deadly" assessment in a private call with Woodward, he told a New Hampshire rally on Feb. 10, "It's going to be fine."
Asked by Stephanopoulos how he responds to former top military advisers in his administration like former Defense Secretary James Mattis and former national security adviser John Bolton who have each publicly said he's unfit for office, Trump painted them as "disgruntled employees."
.@GStephanopoulos: “The people in these top military positions who served most closely with you have said you’re unfit for office. How do you respond to that?”— ABC News (@ABC) September 16, 2020
Pres. Trump: “These are people that I let go. These are disgruntled former employees.” https://t.co/5rferlTBvn pic.twitter.com/E3kBqnrda5
"Mattis was a highly overrated general. He didn't do the job. He didn't do good on ISIS," Trump said, continuing to insist he fired Mattis, though Mattis says he resigned. "John Bolton, all he wanted to do is blow people up."
Presented with the allegations in The Atlantic that Trump made disparaging comments about American troops, Trump slammed the reporting as "fake."
"It's easy because I never made those statements," Trump said, defending that he wanted to visit the cemetery on his 2018 trip to Paris. "As far as John McCain, I was never a fan of John McCain. I never thought he treated our vets well. He didn't do the job. I was never a fan of his. And I think that's fine and everybody knows that and I said it to his face."
READ MORE: Veterans are divided about reports Trump called US war dead 'losers,' 'suckers'
Trump went on to say his actions in office show his support for the military.
Ellesia Blaque, an assistant professor from Philadelphia, who says she voted for Hillary Clinton in 2016 and suffers from a disease called sarcoidosis, asked Trump what he's going to do about people like her with pre-existing conditions -- as he challenges Obamacare in court without having presented a replacement health care plan.
"We're not going to hurt pre-existing conditions and, in fact, just the opposite," Trump said, before falsely claiming Democrats would get rid of protections for preexisting conditions or take on "socialized medicine" although Biden has said he would not support "Medicare for All."
"You've been trying to strike down pre-existing conditions."— ABC News (@ABC) September 16, 2020
In a @ABC2020 town hall, @GStephanopoulos presses Pres. Trump on claim he's preserving pre-existing conditions—as his administration argues in court against Obamacare, which protects them. Watch the full exchange. pic.twitter.com/GuOyqUKhen
"We're going to be doing a health care plan very strongly and protect people with pre existing conditions," he continued, before Stephanopoulos pointed out he still has not presented a plan in his first term as president.
Trump went on to emphasize how he got rid of Obamacare's individual mandate, a financial penalty for not having medical insurance and claim that he has "other alternatives to Obamacare that are 50% less expensive and that are actually better."
"It's been three and a half years," Stephanopoulos said.
"George, it's been 40 years since you had good health care," Trump replied.
Trump also answered questions on police reform.
"I can only say this -- that police in this country have generally done great jobs. There are crimes and problems and there are chokers. They have one-quarter of a second to make a decision and sometimes they make a wrong decision," he says.
Alexander J. Floyd of Dallas, Pennsylvania, who says he voted for Trump in 2016, asked the president how he can balance common sense police reform without sacrificing public safety.
Trump raised the police reform plan Republican Sen. Tim Scott of South Carolina, the only Black Republican in the Senate, spearheaded for the GOP over the summer in the wake of George Floyd's death -- before both parties plans failed in Congress, lacking the necessary bipartisan support.
"The Democrats are viewing this as a political issue, and I probably agree with them, I think it's very bad for them, because we're about law and order. We have to be about law and order otherwise you're going to see your cities burn. And that's the way it is, if we can do a plan like Tim Scott's plan which is really -- it goes far enough, but it doesn't take the dignity away from our police," Trump said.
As protests continue for racial justice across the country, a registered nurse from Glenshaw, Pennsylvania, says she's always voted Republican for president, invoking the names of George Floyd, Breonna Taylor and Jacob Blake, asked Trump if he believes racial injustices are occurring in this nation.
"Well I think they were tragic events, and I do feel that we have to also take into consideration that if you look at our police they do a phenomenal job. You'll have people choke, make mistakes and they happen, it happens, where they have to make a fast decision and some bad things happen," Trump said, adding there are "bad apples" but "99%" are "great people."
Pressed on what he would do about the disproportionate number of Black Americans killed by police, Pres. Trump tells @GStephanopoulos, the police "have done generally a great job,” but some “choke under pressure” and “make the wrong decision.” https://t.co/Uq4PYZysK5 pic.twitter.com/9a91Dotcx2— ABC News Politics (@ABCPolitics) September 16, 2020
"And I will say this, if you're going to stop crime, we have to give the respect back to the police that they deserve," he added. "I agree with you, those events are terrible, but we have to allow the police to do their job. Otherwise crime is going to soar."
Raising the shooting of two sheriff deputies in Los Angeles this week, Trump said the event is an example of "a lack of respect" for law enforcement.
Stephanopoulos also condemned the act before pressing Trump on the fact that Black Americans are more than three times more likely than white Americans to be killed by police.
The president wouldn't say one way or another whether there's a systematic problem with policing.
"No, I think there's problems but I also think there's some very big problems where if you don't give the police back their authority," he said.
Before the town hall, Trump supporters waved flags and held signs hoping to catch a glimpse of the president's motorcade.
"I've been a Democrat my entire life. I walked away from the Democrats a year ago and never looked back," one voter told WPVI-TV.
Before Trump arrived, protesters were also there waiting near the National Constitution Center, some since early in the morning. After the town hall, dozens of others took to city streets, prompting closures, according to Philadelphia officials.
"We're marching for Black lives, against racism, against Donald Trump, Mike Pence--we're demanding change," said protester Brandon Crawford.
"It's not all about one person holding up a sign for a few hours. It's about someone seeing the protest happening, seeing that there's injustice they don't agree with and seeking to educate themselves," added Lupe Fernandez.
According to ABC News, 1 in 4 voters have not made up their minds, but some residents say they know who they want in the Oval Office.
"I am most decided," said Barbara Knowles of Philadelphia. "I tell you, there's no man who has ever put up with what he put up with and he keeps doing it day-to-day."
"He said that he created ten million jobs yet he doesn't talk about the 40 million that are gone. There's so much "BS" that people are just fed up with Trump, so there shouldn't be an undecided voter," said Vincent Squire of Camden, New Jersey.
Pennsylvania is a crucial battleground state. Tuesday was the second time the president has arrived in the state in two weeks.
ABC offered to host a similar town hall for Democratic presidential nominee and former vice president Joe Biden, but ABC and the campaign were not able to find a mutually agreeable date. Biden will have his own town hall on CNN on Thursday.
WPVI-TV, ABC News and the Associated Press contributed to this report.