The $827 billion measure is likely to pass next week despite stiff opposition from the GOP and disappointment among Democrats, including the new president who labeled it imperfect.
Mr. Obama used his weekly radio and Internet address to stress the need to pass the bill, saying it will jump-start the struggling economy and put people back to work.
"We can't afford to make perfect the enemy of the absolutely necessary," Mr. Obama said, sounding a note of pragmatism that liberal followers rarely heard on the campaign trail.
In the Republic response, Republican National Committee Chairman Michael Steele said lots of money in the stimulus package is going to the wrong place.
The popular president - six in 10 voters approve of his performance so far - scolded Republicans with a pointed reminder that Democrats, not Republicans, were victorious in November.
The compromise forged between GOP moderates and the White House came late Friday, reports CBS News correspondent Kimberly Dozier, after a core group of seventeen Democrats and Republicans went through the bill line-by-line, crossing stuff out.
Hours later, the Senate convened a rare Saturday session to debate the compromise, a rare burst of comity aimed at securing passage of the bill with a few Republican votes joining the Democratic majority.
The compromise stripped $108 billion in spending from Mr. Obama's plan, including some destined for projects that likely would give the economy a quick lift. Yet it retained items that probably won't help the economy much at all.
Among the most controversial cuts was the elimination of $40 billion in aid to states, money that economists say is a relatively efficient way to pump up the economy by preventing layoffs, cuts in services or tax increases.
Negotiators left in the package $70 billion to address the alternative minimum tax to make sure families wouldn't be socked with unexpected tax increases averaging $2,300 or so. The problem was going to be fixed later in the year anyway, and congressional economists say fixing the AMT problem helps the economy by surprising little.
While publicly supportive of the bill, White House officials and top Democrats said they were disappointed that so much money was cut, including almost $20 billion for construction and repair of schools and university facilities. Those funds would have supported many construction jobs.
The $827 billion package debated in the Senate on Saturday included the president's signature tax cut of up to $1,000 for working couples. Also included is a tax credit of up to $15,000 for homebuyers and smaller breaks for people buying new cars. Much of the new spending would be for victims of the recession, in the form of unemployment compensation, health care and food stamps.
Mr. Obama himself acknowledged that the bill was far from perfect but said it would be too dangerous to leave it lifeless on the table. He and his advisers have grown more assertive in recent days, reminding Democrats that voters gave them the White House, the House and the Senate to bring change, not partisan gamesmanship.
"In the midst of our greatest economic crisis since the Great Depression, the American people were hoping that Congress would begin to confront the great challenges we face," Mr. Obama said in the address, released before he made his first trip to Camp David, the presidential retreat in the Maryland mountains.
"That was, after all, what last November's election was all about," he said.
Republicans characterized Mr. Obama's rhetoric as arrogant.
"Democrats have controlled both branches of government for less than a month. And you have to wonder if all that power has gone to their heads," Republican National Committee Chairman Michael Steele said in the GOP's weekly address. "For the last two weeks, they've been trying to force a massive spending bill through Congress under the guise of economic relief."
Mr. Obama made an aggressive push for House and Senate lawmakers to work quickly to resolve their differences. The White House plans a major public relations blitz: A prime-time news conference Monday, several trips outside Washington next week and an address to a joint session of Congress later this month.
He had hoped to sign economic legislation on his first day in office, but instead he has spent his first three weeks in office wrangling with a reluctant Congress, including fellow Democrats.
After weeks of losing a public-relations fight with Republicans, Mr. Obama's aides considered any forward movement of his legislation a victory toward fixing the economic crisis that has left 3.6 million Americans without jobs.
Sen. Jon Kyl of Arizona, the Republican's No. 2 in the Senate, criticized Mr. Obama as misrepresenting Republicans' concerns and accused the president of using "dangerous words" in describing the emergency.
"This is still a very big spending bill," Kyl said on the Senate floor as an afternoon session got under way. "You can't fix it by simply shaving a little bit off."
The Senate headed toward a vote early in the week. If, as expected, the bill passes lawmakers will need to resolve the differences between the Senate and House bills before sending a final package to the president.