PHILADELPHIA - Andrew Yang, the entrepreneur-turned-presidential candidate, jogged onto the Philadelphia Art Museum steps made famous by Sylvester Stallone in "Rocky" on Tuesday, fully embracing the underdog plot of his campaign.

Instead of a grey sweatsuit, Yang sported a blue jacket and ball cap, declaring at his rally that he is seeking the presidency to solve the nation's problems. The biggest problem, Yang said, is "How the heck did Donald Trump become our president?"

"I am not a politician. I'm a problem solver. I am an entrepreneur," Yang said. "People will say to me all the time, 'You don't sound like any politician I've ever heard before,' and they aren't complaining."

As Yang spoke, supporters waved signs that said "MATH" in bold white letters, as Yang has positioned himself as a data-driven candidate on a quest to Make America Think Harder. On Tuesday, Yang made a general-election pitch, saying he is one of the only candidates in the field who can attract a sizable share of Trump's supporters and deliver Democrats the presidency.

But Yang's pursuit of the presidency is perhaps improbable. Months after launching his campaign, Yang remains near the bottom of most national polls, but his campaign already has fared better than those of some of the more traditional candidates. Yang was one of 10 candidates to appear onstage at the last presidential debate. And his campaign has outlasted those of a sitting U.S. senator and a sitting governor.

His supporters say his candidacy provides a future-oriented platform that the sprawling Democratic field sorely needs.

"I think that we lost the last election worrying about who was going to win, and it came back to bite us," said Alex Olson, 33, of Philadelphia. "I think you should support who you believe in. I think Andrew Yang is the best candidate by far. He's the only person thinking outside of the box."

"Nevertheless, Yang persisted"

As he waited for Yang to speak, Olson scrawled a handmade sign of support with the words "Nevertheless, Yang persisted." That sign reflects a statement by Mitch McConnell, the Senate majority leader, in 2017 after Republican lawmakers voted to formally silence Sen. Elizabeth Warren - now a Democratic presidential candidate - as she was reading a 1986 letter from Coretta Scott King criticizing Sen. Jeff Sessions' civil rights record.

Olson said he supported Vermont Sen. Bernie Sanders in the 2016 presidential election, describing himself as "Bernie or Bust," but believes Yang is a candidate for his generation.

"I mean, Yang wasn't around," he said when asked what changed his mind. "I love me some Bernie. I think that Yang is better."

Yang has based his campaign around one central proposal: giving every American adult $1,000 a month - what Yang calls a "freedom dividend" - if he is elected president. The idea has gained traction and not just in Silicon Valley, where some prominent figures have expressed support. It also is being experimented with in some cities around the country.

During the presidential debate earlier this month in Houston, he said he would distribute those payments to 10 people for the next year. He has already been distributing $1,000-a-month payments to three families in Iowa, New Hampshire and Florida.

Online Raffle

On Monday, Yang's campaign announced that he had raised $1 million in the 72 hours following the debate and had collected more than 450,000 email addresses from entrants to his online raffle. That $1 million influx positions Yang to best his second-quarter fundraising total of $2.8 million. The third fundraising quarter ends this month.

Still, Yang's haul is likely to be dwarfed by top-tier candidates in the race, including former Vice President Joe Biden, Sanders and Warren.

Daniel Marzec, 31, of Philadelphia, said that after watching Yang in the debates, he'd decided to back Yang over his support for a universal basic income.

"We're a city where we have the lowest per-capita income of any city of our size, and there's not enough discussion about how much a community like West Philly would get every single month with the universal basic income. What that means over time, just that constant investment of resources," he said.