WASHINGTON—President Biden campaigned on rebuilding long-neglected roads, bridges and highways as he sought the presidency last year, pointing to his infrastructure proposal as a way to work with Republicans and deliver on the needs of Americans.

Mr. Biden is now on the cusp of signing the roughly $1 trillion legislation into law, giving him a much-needed bipartisan victory as he grapples with sluggish approval ratings and the aftermath of Republicans’ triumph in Virginia’s off-year elections. Going forward, the legislation...

WASHINGTON—President Biden campaigned on rebuilding long-neglected roads, bridges and highways as he sought the presidency last year, pointing to his infrastructure proposal as a way to work with Republicans and deliver on the needs of Americans.

Mr. Biden is now on the cusp of signing the roughly $1 trillion legislation into law, giving him a much-needed bipartisan victory as he grapples with sluggish approval ratings and the aftermath of Republicans’ triumph in Virginia’s off-year elections. Going forward, the legislation offers the president a ready-made platform to promote construction jobs, ribbon-cuttings and union-friendly groundbreakings around the nation ahead of next year’s congressional elections.

Mr. Biden said the bill, which was approved Friday night by the House on a 228-to-206 vote, will be signed into law soon and he wanted to be joined by lawmakers at a formal signing ceremony. He is also seeking to complete negotiations with congressional Democrats on a broader, nearly $2 trillion social-spending and climate bill. The House approved a rule Friday advancing the larger bill, with plans to vote on it during the week of Nov. 15.

“We did something that’s long overdue, that long has been talked about in Washington but has never actually been done,” Mr. Biden said Saturday in the State Dining Room, noting that he would travel to “some of our ports” next week.

Six progressive Democrats opposed the infrastructure bill, but the legislation picked up the support of 13 Republicans, ensuring passage. Business groups, labor and liberal organizations had backed the measure, pointing to it as a once-in-a-generation opportunity to rebuild crumbling infrastructure.

Rep. Don Bacon (R., Neb.), one of the Republicans who voted for the bill, said he supported it because it would benefit his Omaha-area district. He said fellow Republicans had urged him to vote against it and he was aware that if he and other GOP lawmakers had rejected it, they would have denied Mr. Biden a political victory.

Budget reconciliation may offer Democrats a way to sidestep some partisan gridlock and advance President Biden’s policy objectives. WSJ explains how the process works and why divisions in the party could scuttle the process. Photo Illustration: Carlos Waters / WSJ The Wall Street Journal Interactive Edition

“People wanted me to consider that,” Mr. Bacon said. “And I understand that. But in the end, is the bill right or not? Should we be putting politics in front of what we think is right? That’s what’s being asked of me.”

With a razor-thin majority in the House, Democrats needed 218 votes to pass the bill. If no Republicans had voted yes, Democrats couldn’t have afforded to lose more than three members of their caucus. Thirteen Republican yes votes more than made up for the six Democrats who voted against it.

The infrastructure improvements, which were approved by the Senate in August with 19 Republicans in support, include about $550 billion above projected federal spending on roads, bridges, expanded broadband access and other provisions, such as replacing lead pipes in water systems.

It will inject $110 billion in funding for roads, bridges and major projects, along with another $39 billion to modernize and make public transit more accessible to elderly commuters and the disabled. Major city transit systems, such as New York City’s, will see significant increases in funding based on federal funding formulas.

The spending will be paid for with a variety of revenue streams, including more than $200 billion in repurposed funds originally intended for coronavirus relief but left unused; about $50 billion from delaying a Trump-era rule on Medicare rebates; and $50 billion from certain states returning unused unemployment insurance supplemental funds.

“It’s going to be a monumental, long-term investment,” said Rep. Gerry Connolly (D., Va.), who noted the nation is still benefiting from the nation’s Interstate Highway System ushered in by President Dwight D. Eisenhower during the 1950s. “It is still reaping an economic return on that investment.”

And for a president who commuted daily from his Delaware home to the Senate for more than three decades aboard an Amtrak commuter train, the provisions include $66 billion in rail maintenance, modernization and expansion, most of which will go to Amtrak.

Mr. Biden made infrastructure improvements a key part of his 2020 campaign, often pointing to the projects as a way to address resiliency from the impact of climate change and appeal to blue-collar workers in states such as Michigan, Wisconsin and Pennsylvania, which he carried in his race against former President Donald Trump.

Sean McGarvey, president of North America’s Building Trades Unions, said throughout the process Mr. Biden emphasized the importance of the bill in terms of competing with China and maintaining the nation’s economic role around the world.

“He would not take no for an answer and he leaned in and he leaned in and he leaned in and he wanted to make it bipartisan,” Mr. McGarvey said. “He’s done more for the poor, the working-class and the middle-class in this country than any president in my lifetime for sure.”

The infrastructure bill is expected to play a prominent role in Mr. Biden’s pitch to voters ahead of next year’s midterm elections, in which Democrats will attempt to maintain their narrow majorities in the House and Senate.

That control has been thrown into doubt following Tuesday’s off-year elections, which saw a former private-equity executive, Republican Glenn Youngkin defeat Democratic former Gov. Terry McAuliffe in Virginia’s race for governor, a state which Mr. Biden won handily last year. In solidly blue New Jersey, incumbent Democratic Gov. Phil Murphy narrowly defeated his Republican opponent to win a second term.

White House officials have held initial calls to begin planning for the rollout of the infrastructure upgrades, coordinating with labor groups, progressive organizations and others, according to people familiar with the calls. Mr. Biden is expected to hold events around the country to promote the new law.

In addition to the president and Vice President Kamala Harris, members of Mr. Biden’s cabinet are expected to be heavily involved in the push, including Transportation Secretary Pete Buttigieg, Energy Secretary Jennifer Granholm, Interior Secretary Deb Haaland, Commerce Secretary Gina Raimondo and Michael Regan, the administrator of the Environmental Protection Agency, a White House official said.

An agreement on infrastructure spending had eluded Mr. Trump and many of his predecessors in the White House despite garnering bipartisan support. But the bill’s popularity—and Mr. Biden’s decision to make it a bipartisan centerpiece of his first year in office—helped it throughout the process.

Rep. Emanuel Cleaver (D., Mo.), recalled attending a summertime event in Lawson, Mo., a small rural community northeast of Kansas City, in which he spoke about the bill’s potential to repair a local bridge. “I mentioned the bridge and the crowd erupted,” he said.

“There’s not a person in there,” Mr. Cleaver said of his congressional colleagues, “Republican, Democrat, short, tall—who is not going to be thrilled that bridges and decrepit roads in their district are going to be repaired or replaced.”

Republican opponents warned that the bill wasn’t fully paid for—the Congressional Budget Office found that the bill would increase the federal budget deficit by $256 billion over 10 years—and said only a small portion of the legislation was devoted to rebuilding roads and bridges.

“I believe we could have done more with less if done in a truly bipartisan and pragmatic way,” said Rep. Nancy Mace (R., S.C.).

Now, Mr. Biden will need to sell the benefits to voters. As vice president, he often urged former President Barack Obama to do more to promote the elements of the economic recovery package during the depths of the recession.

More recently, Mr. Biden acknowledged that his own attempts to publicize the $1.9 trillion Covid-19 relief package, his biggest legislative achievement up to this point, was undermined by a series of events during the summer, including hurricanes and wildfires and the chaotic Afghanistan evacuation.

With the infrastructure funding soon to be pumped into the economy, Mr. Biden will be tasked with showing how it makes a difference in the lives of Americans.

“What’s going to sell it is there is going to be a hell of a lot of work out there for contractors and small businesses and workers starting next construction season,” said Rep. Peter DeFazio (D., Ore.), the chairman of the House Transportation and Infrastructure Committee. “People will feel better about their lives when they’re earning good paychecks.”

But Mr. DeFazio said it would be up to Democrats to ensure the public knows about the new law. “We don’t sell ourselves enough, I guess. We’ve got to work on that.”

—Siobhan Hughes contributed to this article.

Write to Ken Thomas at ken.thomas@wsj.com and Lindsay Wise at lindsay.wise@wsj.com