Biden takes his State of the Union message to 2024 battlegrounds, starting in Philly

President Joe Biden headed to battleground Pennsylvania on Friday to build on momentum from his State of the Union, kicking off a major ramping up of his reelection campaign.

Biden was joined by the first lady at an event on the outskirts of Philadelphia -- the first test as to whether he can keep up the energy and forceful rhetoric that he showed in Thursday night's high-stakes speech.

"So, did you all see Joe last night? Wasn't he on fire?" Jill Biden asked the crowd as she introduced her husband. "I was so proud of him, you know, he gave such a strong speech and set out a clear vision of where we've been and where we're going."

When Biden took the microphone next to rousing applause, he played off Thursday night's speech as well, showing some of the same energy. "If you're tired, you probably watched my address last night. I got my usual warm reception from Congress and Marjorie Taylor Greene," he said to laughs.

Fired up, he stressed some of the same themes, but this time mentioned Donald Trump's name at least seven times -- after referring to him repeatedly only as his "predecessor" Thursday night.

"In my address I spoke about how far we've come since we took office. I talked about how much is at stake," he said. "Folks, our freedoms really are on the ballot this November. Donald Trump and the MAGA Republicans are trying to take away our freedoms. That's not an exaggeration. Well, guess what, we will not let him. We will not let him!."

Thursday night, Biden used the national stage -- one of his biggest before the November election -- to confront Republicans and his 2024 rival while laying out his own accomplishments and what else he wants to get done while in office (and if given another four years).

While the president didn't say "Donald Trump," he mentioned his "predecessor" more than a dozen times. He accused Trump of bowing to Russian President Vladimir Putin, trying to bury the truth of what happened on Jan. 6 and tanking a bipartisan immigration bill.

The Biden campaign told ABC News they chose Pennsylvania's Delaware County for Friday's event to reach suburban voters in a critical swing state. Trump has underperformed in the suburbs, and Biden's team is hoping they can pick up supporters there that backed Nikki Haley in the Republican primary over the former president.

This is just one of several visits the President will be making to battleground states in the coming weeks. Over the weekend Biden will hold an event in Georgia, and next week he'll campaign in Wisconsin and Michigan.

The travel is part of a significant build-up in campaign operations. The campaign also announced a $30 million advertising blitz and the scaling up of state-level operations, hiring hundreds of news staff, and increasing volunteer opportunities.

Jen O'Malley Dillon, the campaign's chair, said this new phase will prepare them for a Trump rematch. The former president is all but certain to be the Republican nominee after cruising through Super Tuesday, prompting the last major GOP rival to exit the race.

"I think that really just showcases the strength that we are really positioned for this perfect moment in time, this inflection point, headed into the general election versus Trump," O'Malley Dillion said of the new initiatives. "Trump's bleeding cash, he's really behind in building the infrastructure that you'd expect to be seeing of a former president."

Biden's fiery performance on Thursday night quelled anxieties among Democrats about his stamina and fitness, but he'll have to keep it up over these next eight months. Polling has consistently shown his age (81) is a top concern for voters.

Addressing his age in Thursday's address, Biden sought to flip the script by attacking Trump, who is 77, as having outdated ideas that will move the country in the wrong direction -- a line he'll likely repeat on the campaign trail.

"My fellow Americans, the issue facing our nation isn't how old we are, it's how old our ideas are," he said. "Hate, anger, revenge, retribution are among the oldest of ideas. But you can't lead America with ancient ideas that only take us back."

Yet, some voters ABC News spoke with in the swing state of Pennsylvania said they were unimpressed by Biden's fiery speech. For many of them, the border and economy are top of mind -- issues they believe the president hasn't delivered on.

"He sounded very angry", Jayne Kovich, a registered Democrat said. "I don't think he's really in touch. Like he doesn't go to the grocery store. He doesn't go and buy the burgers that, you know, at McDonald's and that and it's like crazy -- prices are crazy.

"He didn't bring up anything about the border//until like almost 40 minutes into it."

For Kovich, even though she's a registered Democrat, she said her choice for president will be a game time decision in November.

"I don't know if I really want to go with Trump either// the day of I'll decide," she said.

Kovich added that during the Trump years, "everybody seemed like they had more money in their pockets. And it just seemed like -- everything seemed safer."

Eugene Lopez, who supports Trump, said the president "put up an act" in his speech Thursday night. The border is also a key issue for Lopez, who says he doesn't buy the president blaming the crisis on Republicans.

"The economy, the border – the lying about the border? People see it," Lopez said

The Biden supporters ABC News spoke with, meanwhile, felt reassured by his performance.

"I think he just nailed it," Renee Gentzel said. "He showed up last night and he looked raring to go."

Gentzel said she's not concerned about his age."I felt like he was with it. He knew what was going on."

ABC News' Alexandra Hutzler contributed to this report.