President Biden told a Pennsylvania labor union that Republicans cannot be trusted to put workers’ interests over corporate ones, using a victory lap over a 2021 pension measure to offer tacit support for Vice President Kamala Harris on the cusp of Tuesday’s election.

Speaking in Philadelphia, Mr. Biden touted the Butch Lewis Emergency Pension Plan Relief Act of 2021, legislation meant to shore up multi-employer pension plans. It passed as part of Mr. Biden’s broader coronavirus-relief plan.

“Not a single, solitary Republican in the House or the Senate voted to help with the pensions, not one single one,” Mr. Biden told the United Food and Commercial Workers Local 1776 in Philadelphia, a Democratic stronghold in swing-state Pennsylvania.

Mr. Biden said another $684 million would be released to restore pensions for 29,000 UFCW members.

“Thank you, Joe,” the crowd shouted.

“You earned it,” Mr. Biden said.

The legislation was named for the late Estil “Butch” Lewis of Ohio, a Vietnam War veteran and union member who championed pension reform.

Mr. Biden shocked his widow, Rita, by awarding Lewis with a posthumous Citizens Medal, which is given out for “exemplary” service to Americans.

Union members teed up the president’s speech by accusing Republican nominee former President Donald Trump of doing nothing to help unions before Mr. Biden passed his American Rescue Plan to bolster their retirement savings.

“He didn’t do a damn thing!” Mr. Biden said in agreement when he got to the microphone.

Ms. Harris and Mr. Trump are in a statistical tie with few days to go until Election Day. The race likely will be decided by tens of thousands of votes in seven battleground states.

Union households are critical to winning this year’s election.

In the battleground states of Michigan, Nevada and Pennsylvania, roughly 15% of employees are union members. The number of union workers in the three states combined exceeded the margin of victory in those states during the 2016 and 2020 elections.

The International Brotherhood of Teamsters declined to endorse Ms. Harris or Mr. Trump. It said neither candidate could win sufficient support from members.

That was viewed as a blow to Ms. Harris, who like Mr. Biden has courted union leaders for support.

While most labor unions have endorsed Ms. Harris, she has struggled with rank-and-file members, a group that has traditionally backed Democrats.

An internal Teamsters poll found that its Michigan members preferred Mr. Trump (61.7%) over Ms. Harris (35.2%), prompting the national union’s leadership not to make an endorsement in this year’s presidential race.

Ms. Harris also failed to gain the support of the International Association of Firefighters.

The National Border Patrol Council endorsed former Mr. Trump at a campaign rally in Arizona last month, saying the GOP nominee would end the chaos at the U.S.-Mexico border “once and for all.”

Mr. Biden said his side is the only one that can be trusted to follow through on its promises.

“One thing I don’t think anyone can argue is, I never haven’t done what I said I was going to do,” Mr. Biden said.

Mr. Biden courted workers hours after an underwhelming jobs report showed the U.S. added only 12,000 jobs in October, far short of expectations.

The White House said back-to-back hurricanes and the machinist strike at Boeing amounted to anomalies that suppressed the numbers, while Republicans saw it as proof that Biden-Harris policies aren’t working.

• Jeff Mordock contributed to this report.