Moderator Chris Wallace has repeatedly tried to keep Trump from interrupting Biden.

"It's hard to get any word in with this clown," Biden said, "excuse me, this person."

Amid bombshell reporting in the New York Times on the past two decades of Trump's taxes, Wallace put the first question to the president.

"Is it true that you paid $750 in federal income taxes?" Wallace asked.

"I paid millions of dollars in taxes," Trump responded. "Millions of dollars of income tax."

But the president never fully answered if that was federal income tax.

Trump paid just $750 in income taxes in 2016, the year he ran for president, and in 2017, his first year in the White House, according to the Times report.

Biden, meanwhile, paid nearly $288,000 in federal income taxes last year, according to returns he released just hours before his Tuesday night debate, an effort to draw a sharp contrast with the revelations about Trump's tax returns.

Democrats said if the president is upwards of $400 million in debt as the New York Times has reported, he poses a national security threat to the country.

Wallace pressed on, asking "Mr. President, I'm asking you a question. Will you tell us how much you paid in federal income taxes in 2016 and 2017?

"Millions of dollars," Trump replied.

The president then blamed Biden for the tax codes since Biden has worked for so long in Washington.

"I'm going to eliminate the Trump tax cuts," Biden said.

"You are the worst president America has ever had," Biden continued.

"Let me just say, I've done more in 47 months than you've done in 47 years, Joe," Trump replied.

In a heated discussion on tax policy, Biden criticized Trump's trade policies with China which led to the first thinly veiled mention of Hunter Biden on stage.

"He talks about the art of the deal. China's perfected the art of the steal. We have a higher deficit with China now than we did before, we have the highest deficit -- trade deficit with Mexico," Biden said, before Trump interrupted.

"China ate your lunch, Joe. And no wonder your son goes in and he takes out what he takes out, billion of dollars," Trump said, before launching personal attacks on Biden's son, Hunter Biden, and his business dealings while his father was vice president. Hunter Biden has denied any wrongdoing.

"We want to talk about families and ethics? I don't want to do that. I mean his family, we can talk about all night," Biden responded, then said the American people don't want to hear about their families.

Asked about how they would deal with economic recovery, Trump said he would avoid further shutdowns, touted the current economic recovery and credited himself with bringing back college football.

"Our country is coming back incredibly well, setting records as it does it. We don't need somebody to come in and say let's shut it down," Trump said, though Biden said he would not impose a full shutdown as the president suggested.

Biden then took the opportunity to speak directly to American families on Trump's taxes and repeated his mantra that the U.S. "can't fix the economy without fixing COVID."

"The difference is millionaires and billionaires like him in the middle of the COVID crisis have done very well," Biden said. "You folks living in Scranton and Clayton and all the small towns and working-class towns in America: How well are you doing?"

Despite Republican successes in statewide races in Ohio since 2016, the Buckeye State has become increasingly competitive as Trump and former vice president Joe Biden prepare to face off in Cleveland for their first debate on Tuesday.

In recent weeks Trump and Vice President Mike Pence have traveled repeatedly to Ohio, where they defeated Hillary Clinton and Sen. Tim Kaine, D-Va., her vice presidential candidate, in 2016, 51% to 43%.

Republicans also performed well statewide two years ago, winning the gubernatorial race and other down-ballot contests.

“Ohioans showed up for President Trump in 2016 and we expect them to do the same this November,” Trump campaign spokeswoman Samantha Zager told ABC News.

The president’s campaign has had a permanent presence on the ground in Ohio since 2016, and said they have made more than 10 million voter contacts in the state, where they and other GOP groups continue to canvass on the ground during the coronavirus pandemic.

The Biden campaign, meanwhile, has relied on virtual and digital organizing in the state during the pandemic, and has hosted hundreds of events and held 450,000 conversations with voters over the last month. Following Tuesday's debate, Biden will take a train tour of the state on Wednesday.

Biden has delivered a sharp economic message focused on Trump's record, centered on Toledo and Youngstown, home to several car plants and many blue-collar voters who abandoned Democrats and voted for Trump for years ago.

He's run at least eight television ads in recent weeks, including a response to Trump's call for a ban on Goodyear, the Ohio-based tire company than ran in Akron, where the company is based.

In an election year reshaped by the coronavirus pandemic, it’s also playing host to a number of legal battles over access to ballot drop boxes, which are increasingly used by voters as an alternative to in-person voting or relying on the United States Postal Service, amid concerns about service delays.

Read more about the battle for Ohio here.

-ABC News' Ben Siegel and Adia Robinson