President Trump campaigned Thursday in one of the most Democratic counties in the nation, holding a rally at the South Bronx as he tries to woo minority voters days before a Manhattan jury will begin deliberations on whether to convict him of felony charges in his criminal hush money trial.

Mr. Trump addressed supporters in Crotona Park, a public green space in a neighborhood that is among the city’s most diverse and its most impoverished, a change from the majority-white areas where he holds most of his rallies.

While the crowd was not quite as diverse as the South Bronx as a whole, it included large numbers of Black and Hispanic voters; Spanish was heard throughout the crowd.

Mr. Trump, in his speech, cast himself as a better president for Black and Hispanic voters than President Biden as he railed against the incumbent on immigration, an issue Trump has made central to his campaign. 

He insisted “the biggest negative impact” of the influx of migrants in New York is “against our Black population and our Hispanic population who are losing their jobs, losing their housing, losing everything they can lose.”

Some in the crowd responded by chanting, “Build the wall,” a reference to Mr. Trump’s push while in the White House to build a border barrier.

With Mr. Trump confined to New York for much of the last six weeks because of his trial, the presumptive Republican nominee’s campaign has planned a series of local stops across his hometown before and after court. He visited a bodega at Harlem, dropped by a construction site and held a photo op at a local firehouse.

The Bronx rally was his first event open to the general public as he insists he is making a play to win an overwhelmingly Democratic state that hasn’t backed a Republican for president since Ronald Reagan in 1984. 

Besides creating a spectacle of rallygoers and protesters, the rally also gave Mr. Trump an opportunity to highlight what he argues are advantages on economic and immigration issues that could cut into key Democratic voting blocs.

“The strategy is to demonstrate to the voters of the Bronx and New York that this isn’t your typical presidential election, that Donald Trump is here to represent everybody and get our country back on track,” said Representative Byron Donalds of Florida, a potential Trump running mate who grew up in Brooklyn and spoke at the rally.

The former president opened his rally with an ode to his hometown, talking about its humble beginnings as a small Dutch trading post before becoming a glamorous capital of culture that “inspired the entire world.” 

While Mr. Trump established residency in Florida in 2019, he reminisced on Thursday about his efforts to revitalize Central Park’s Wollman Rink and people he knew in the real estate business.

“Everyone wanted to be here,” he told the enthusiastic audience. “But sadly this is now a city in decline.”

“If a New Yorker can’t save this country,” he went on to say, “no one can.”

The Bronx Democratic Party protested Trump’s appearance with its own event at the park.

Members of multiple unions were present, holding signs that said “The Bronx says no to Trump” in both English and Spanish.

“We are used to elected officials, to government officials, to opportunists of all kinds who come to our community and use our painful history,” said a Democratic state representative, Amanda Septimo, who represents the South Bronx. 

“They talk about the Bronx and everything that’s wrong with it, but they never get to the part that talks about what they’re going to do for the Bronx and we know that Trump is never going to get to that part in his speech.”

Some locals in the crowd Thursday disagreed.

Margarita Rosario, a 69-year-old who has lived in the borough for more than 60 years, said she saw Representative Alexandria Ocasio-Cortez of New York on television the night before suggesting that the Bronx wouldn’t support Trump. It spurred her to show up, holding a Trump flag and a poster that said, “Make America Great Again.”

“I got so annoyed with that. I said, ‘How dare she speak for the whole Bronx?’” Ms. Rosario said.

Muhammad Ali, a 50-year-old who lives in the Bronx and said he planned to vote for Trump in November, said he once used to think the former president was a racist but his views have changed.

“We need a patriotic president at the moment and I find Donald Trump more patriotic for the moment than Joe Biden,” said Mr. Ali, an immigrant from Bangladesh and worker for New York’s transportation agency.

At least one New Yorker in the crowd said he knew Mr. Trump from his days as a local billionaire real estate developer.

Alfredo Rosado, 62, said he’d been a Trump supporter since 1998 when he worked for several months as a fill-in summer doorman at Trump Tower.

Mr. Rosado recounted how Trump had asked his name and stopped to chat. “He’s the same person you see,” he said of the former president.

Mr. Trump’s campaign believes he can chip away at Mr. Biden’s support among Black and Hispanic voters, particularly younger men who may not follow politics closely, but are frustrated by their economic situations and drawn to Mr. Trump’s tough persona.

He’s also argued the indictments he faces in New York and elsewhere make him relatable to Black voters frustrated by the criminal justice system, a statement that was harshly criticized by Mr. Biden’s allies.

The rally comes during a pause inMr.  Trump’s criminal hush money trial. Court will resume following the Memorial Day weekend with closing arguments. 

The jury will then decide whether Mr. Trump will become the first former president in the nation’s history to be criminally convicted and whether he will be the first major party presidential candidate to run as a convicted felon.

The Bronx was once the most Democratic borough in the city. President Obama won 91.2 percent of the borough’s vote in 2012, the highest in the state. Mr. Biden won 83.5 percent of the borough in 2020. Mr. Trump garnered 16 percent  of the vote.

The area Mr. Trump visited is overwhelmingly non-white — a departure from most of his rally locations. About 65 percent of residents are Hispanic and 31 percent Black, according to the U.S. Census data. About 35 percent live below the poverty line.

As he wrapped up his speech, Mr. Trump said he woke up Thursday uncertain of the reception he’d get in the Bronx.

“I said, ‘I wonder, will it be hostile or will it be friendly?’” he said. “It was beyond friendly. It was a lovefest.”