"After the disaster of the last eight years, we need somebody to lead us in an American reclamation project," the New Jersey rocker said.
Springsteen said that America remains a house of dreams for some, but that too many people have given up on the promise of fairness and equality.
"I've spent 35 years writing about America and its people and the meaning of the American promise - a promise handed down right here in this city," said Springsteen, whose songs often depict down-on-their-luck, working-class dreamers. "Our everyday citizens ... have justifiably lost faith in its meaning."
The rally, planned by the Obama campaign just a week ago, drew tens of thousands of people to the Benjamin Franklin Parkway. Springsteen himself approached the campaign and asked to help out, an Obama aide said. The Philadelphia event came just days before Monday's voter registration deadline in Pennsylvania.
"The Boss" also plans to perform at Obama gatherings in Ohio on Sunday and Michigan on Monday. On Oct. 16, he will join Billy Joel at an Obama fundraiser in New York City.
Springsteen cited the Iraq war, the recent economic turmoil and Hurricane Katrina as examples of the Bush administration's failures. He bookended the set with his rock classic "Promised Land" and Woody Guthrie's folk anthem, "This Land is My Land."
Nurse Donna Waters, 46, of Camden, N.J., appreciated the Katrina reference. She wore a black baseball cap adorned with the New Orleans fleur de lis, as she does each day, to remember "what our government did to our people."
Waters is African American, but believes the Katrina response was motivated more by class than race.
"It seems like those that have, get. And those that don't have are going to be forgotten," said Waters, an Obama supporter.
The Obama camp says its registration efforts have helped give Democrats a 1.2 million-voter advantage over Republicans in Pennsylvania, up from a 580,000-voter lead in 2004. The most recent Quinnipiac University poll, conducted late last month, showed Obama with a 54 percent to 39 percent lead over Republican John McCain among likely state voters.
Artist Colleen Dougherty-Bronstein, 55, of Yardley, was perhaps one of the few undecided voters on hand.
"I have concerns about both candidates," she said. "Are either of them strong enough to take on the mess that they'll be going on to?"
More shared the pro-Obama views of college student Allison Scott, 20, of Adamstown, Md., and her father, systems analyst Jim Scott.
"Frankly, when I look at Obama's program, it will probably cost me $3,000 in taxes," said Scott, who said he once supported the Iraq war. "But I don't know that there'd be much of a country to turn over to my children" otherwise, he said.