JD Vance greeted by both jeers and cheers at firefighters convention in Boston, following Tim Walz

"Sounds like we got some fans and some haters," he said. "That's okay."

Republican vice presidential nominee JD Vance spoke at the International Association of Fire Fighters Convention in Boston on Thursday, the day after Democratic vice presidential nominee Tim Walz spoke at the same event.

Both candidates are battling for support from one of the largest labor unions, which represents nearly 350,000 workers.

An IAFF spokesperson told Boston.com that both campaigns reached out to the union about speaking at the event, but they did not disclose an exact timeline of when each candidate did so.

After being introduced by Rep. Carlos Giménez, R-Fla., Vance was met with a mix of boos and cheers as he took to the stage.

“Sounds like we got some fans and some haters,” he said. “That’s okay.”

Vance started his speech speaking about his mother, who he said struggled with addiction.

“Believe it from me, believe it from a kid who’s seen it with his very own eyes,” Vance said. “We wouldn’t have the second chance with my mom without probably some of the people that are sitting in this room.”

Vance said he is “proud” to be a “populist,” and framed former President Donald Trump as a “different kind of Republican.”

“Our enemies and a lot of Democrats call us populists, like it’s something of an insult,” Vance said. “If being a populist means being on the side of working people, rather than the powerful elites who hollowed out our middle class and sent us into stupid foreign wars, then sign me up.”

The Ohio senator asked the union, which endorsed Joe Biden for president in 2020 but has yet to announce an endorsement in this race, to consider supporting the Republican ticket this time around.

“Now for decades, unions have given support to Democrat candidates without giving Republicans much consideration,” Vance said. “After supporting Democrats for so long in this union, what has it gotten you?”

The IAFF spokesperson told Boston.com that there is no set schedule for when they might make a potential endorsement.

Vance acknowledged the “diverse” political views of the union and credited his firefighter friend from Dayton, Ohio for changing his mind about Trump.

“Some of you love President Trump, and some of you clearly don’t,” he said. “[Trump] changed my mind and he won my vote, and for the skeptics still out there, I hope he has changed your minds too.”

On Wednesday, Walz also recognized the bipartisan demographic of his audience and made an appeal to Republicans and undecided candidates in the room.

“When Republicans used to talk about freedom, they meant it — not anymore,” Walz said. “These guys over there, they want government to have the freedom to invade every corner of your life, from our union halls, to our kids’ schools, even our doctor’s offices.”

But Vance said Trump “cares for working people.”

“A lot of Democrats want to attack Republicans as being anti-union, and sometimes the shoe fits, but not me and not Donald Trump,” he said.

In his speech, Walz had taken shots at Vance and Trump for their attitudes toward workers and about Project 2025.

“The only thing these guys know about working people is how to take advantage of them,” Walz said. “Project 2025 is a plan to reshape what America looks like, moving away from the middle class and putting it right back up to oligarchs and the wealthy at the top.”

Vance asked for the union’s support and endorsement.

“I want your support,” Vance said. “We’re going to fight for you, whether we get it or not.”