Delegates from the Senate and House of Representatives, picked to resolve differences between the chambers' rival versions of the economic legislation, were beaming as they announced Obama's biggest legislative success yet.
Democratic Senate Majority Leader Harry Reid told reporters: "The difference between the Senate and House versions we've resolved. The bills were really quite similar.
"And I'm pleased to announce that we've been able to bridge those differences," he said, expressing his hope to have a vote in both chambers of Congress "within the next few days, maybe as early as tomorrow."
Senator Susan Collins, one of the centrist Republicans whose support was crucial to getting Obama's mammoth plan through the Senate, said the compromise bill mixing hefty investment and tax cuts totaled $789 billion.
Independent Senator Joseph Lieberman said the stimulus package marked "the beginning of the turnaround for the American economy."
"It will create or protect millions of jobs. It will put billions into the pockets of hard-working Americans," he said.
Earlier Democratic Senate Finance Committee chairman Max Baucus, a key Obama ally, said the package would likely pass this week.
"It's very possible that the House will pass its version ... tomorrow and we'll take it up either tomorrow night or Friday, unless there are some procedural hoops we have get through," he said Wednesday.
"The votes are there for passage. That is clear," Baucus said as he and fellow negotiators, who worked on the compromise late into the night on Tuesday, took a lunch break. "And I know they will not change."
With lawmakers racing to meet a self-imposed goal of passing a final deal by February 16, Baucus said all sides had compromised and added: "Nothing like a deadline to force people to start to give and take a little."
Obama's Republican critics, all of whom voted against the stimulus in the House and just three of whom joined the Democratic bloc in the Senate, reacted to the news by appealing for the legislation to be put online for 48 hours so the US public could read the text before it heads to a vote.
Obama, meanwhile, pursued an aggressive political and public relations blitz to win support from wavering lawmakers, trekking to a construction site in northern Virginia to tout what he called his "urgent" and "essential" plan.
"We've got to get a final version to my desk so that I can sign it," said the president, hoping for a big legislative win after his young presidency suffered a series of early setbacks.
Vice President Joe Biden was also to visit infrastructure construction projects to push for the measure, which includes tens of billions to build or fix key parts of the crumbling US network of roads, bridges and levees.
But the decisive balancing act was in the marbled halls of the US Capitol, as the 10 negotiators sought to bolster job-creating parts of the package but keep the price tag at current levels in order not to lose a handful of Republicans who made the difference in the Senate's approval.
Three moderate Republicans - Collins and her fellow Maine Senator Olympia Snowe, and Pennsylvania Senator Arlen Specter - are key for the Democrats' reliable 58-vote bloc to push past the 60 votes needed to overrun any parliamentary delaying tactics.
Baucus said the ‘Buy American’ restriction on stimulus dollars - diluted but not banished by the Senate in the face of worries among key US trading partners like Canada and Europe - had "not even come up."
Republicans, outgunned in both chambers, continued to denounce the plan as wasteful and lacking much-needed tax cuts, and appealed to Obama to help get some of their ideas into the final bill.
"We're hopeful, hopeful that it's not too late. The president can still intervene," House Minority Leader John Boehner said. "Bring us into the process so that we'll have a bill that actually works."