WASHINGTON — President Biden is planning an aggressive campaign to tell voters about the benefits for them in the $1.9 trillion economic relief package that won final congressional approval on Wednesday, an attempt to ensure that he and his fellow Democrats get full political credit for the first big victory of his administration.

The effort will start with Mr. Biden’s scheduled prime-time address to the nation on Thursday and include travel by the president and Vice President Kamala Harris across multiple states, events with a wide range of cabinet members emphasizing themes of the legislation and endorsements from Republican mayors, administration officials said on Wednesday.

The White House’s decision to get out and sell the package after its passage reflects a lesson from the early months of the Obama administration. In 2009, fighting to help the economy recover from a crippling financial crisis, President Barack Obama never succeeded in building durable popular support for a similar stimulus bill and allowed Republicans to define it on their terms, fueling a partisan backlash and the rise of the Tea Party movement.

Mr. Biden starts with the advantage that the legislation, which he is set to sign on Friday, is widely popular in national polling. And it will deliver a series of tangible benefits to low- and middle-income Americans, including direct payments of $1,400 per individual, just as the economy’s halting recovery from the pandemic recession is poised to accelerate.

Speaking briefly to reporters on Wednesday, the president called the legislation “a historic, historic victory for the American people.”

After his address from the Oval Office on Thursday night, Mr. Biden will headline a public relations effort over several weeks that aides say will involve his entire cabinet and White House communications officials, and support from like-minded business and policy organizations and political supporters at all levels around the country. The White House announced on Wednesday that Mr. Biden would visit the Philadelphia suburbs next week.

Unlike President Donald J. Trump, who loved to serve at times as a singular pitchman for the economic policies under his administration, Mr. Biden will lead an all-hands effort.

It is a striking contrast to the strategy pursued by the Obama administration, when Mr. Biden was vice president. Mr. Obama’s first major legislative victory was a nearly $800 billion stimulus bill that passed with the backing of a majority of voters, but it lost support over time.

Mr. Biden was still trying to sell voters on the benefits of that plan in 2016, near the end of his time as vice president. He told congressional Democrats this month that the administration had “paid a price” for failing to better market the bill early on.

Mr. Obama struggled in part because the economy was still contracting when his plan passed, and its rollout was overshadowed by an arduously slow recovery from recession. “President Obama gave speech after speech” to sell his stimulus plan, Dan Pfeiffer, who was a White House communications director under Mr. Obama, wrote this week. “He visited factory after factory that had reopened because of the Recovery Act. But it was nearly impossible to break through the avalanche of bad news.”

The circumstances appear to be different this year. Democrats are buoyed by polls that show Mr. Biden’s relief package winning as much as three-quarters support from voters nationwide, including large swaths of Republicans, even after a month of attacks from congressional Republicans who voted in unison against its passage in both the House and the Senate.

More than 7 in 10 Americans backed Mr. Biden’s aid package as of last month, according to polling from the online research firm SurveyMonkey for The New York Times. That includes support from three-quarters of independent voters, 2 in 5 Republicans and nearly all Democrats. A poll released on Tuesday by the Pew Research Center found similar support.

The Biden team also appears to have economic circumstances working in its favor. Job growth accelerated in February, Mr. Biden’s first full month in office. Forecasters expect economic growth to speed up even more in the months to come because of the increasingly widespread deployment of Covid-19 vaccines across the country, which should allow consumers to start spending more on activities like traveling or dining out, which many have cut back on over the past year because of the pandemic.

Forecasters expect the relief package to further fuel growth, in part by shuttling money to low- and middle-income Americans who disproportionately lost jobs and incomes in the crisis. The O.E.C.D. predicted this week that the Biden plan would help the United States economy grow at a 6.5 percent rate this year, which would be its fastest annual clip since the early 1980s.

The timing of the bill could bolster Mr. Biden’s attempts to claim credit for that rebound, even though forecasters were projecting a return to growth — albeit a smaller one than they now predict — before he took office. Mr. Trump did something similar in 2017: Growth had slowed in early 2016, but it had begun to improve in the second half of that year, before Mr. Trump won the White House. Yet he persistently claimed he had engineered the greatest economy in American history.

Still, Biden administration officials are mindful that political opposition could easily fester and grow if they do not clearly explain the contents — and direct benefits — of a bill that will be the second-largest economic aid package in American history, trailing only the initial bill that lawmakers approved under Mr. Trump last year as the worsening pandemic pushed the nation into recession.

Republicans continued to attack the bill on the House floor on Wednesday, casting it as overly expensive, ineffectively targeted and bloated with longstanding liberal priorities unrelated to the pandemic.

“Because Democrats chose to prioritize their political ambitions instead of the working class,” Representative Jason Smith of Missouri, the top Republican on the Budget Committee, said in a news release, “they just passed the wrong plan, at the wrong time, for all the wrong reasons.”

Senator Sherrod Brown of Ohio, one of the few Democrats in the chamber to represent a state Mr. Biden lost to Mr. Trump in 2020, called the Republican attacks “lies” and said they showed why Democrats needed to remind voters of the benefits to people and businesses included in the bill.

“You’ve got to sell it, because they’re going to lie about everything,” Mr. Brown said. “The sale is an easy sell, but you need to continue to remind” voters about the contents of the package, he said.

With that in mind, Mr. Biden is scheduled to follow his speech on Thursday with travel to states led by both Democratic and Republican governors in the coming weeks to begin the sales pitch. Among the options being considered, if they can be done safely during the pandemic, are town-hall-style events that allow the president to directly take questions from people.

The main message, according to Jen Psaki, the White House press secretary, will be an echo of one of Mr. Biden’s chief campaign promises: “Help is on the way.”

The president’s political and communications advisers have identified 10 themes that they want to tackle, one by one, in the days and weeks ahead. They include food insecurity, child poverty, bolstering rural health care, school reopening, help for veterans and help for small businesses.

“We’ll be emphasizing a number of components that are in the package and really having a conversation,” Ms. Psaki said. “This is important to the president personally, having a conversation directly with people about how they can benefit, addressing questions they have, even taking their feedback on implementation.”