Hillary Rodham Clinton, Obama's chief Democratic rival, said she was glad Obama had given the speech.
"Issues of race and gender in America have been complicated throughout our history, and they are complicated in this primary campaign," said Clinton, also campaigning in Philadelphia. "There have been detours and pitfalls along the way, but we should remember that this is a historic moment for the Democratic Party and for our country. We will be nominating the first African-American or woman for the presidency of the United States, and that is something that all Americans can and should celebrate."
Obama's speech also drew praise from one of his former Democratic presidential rivals who has not endorsed him or Clinton. Delaware Sen. Joe Biden called it powerful, truthful and "one of most important speeches we've heard in a long time"
"He told the story of America -- both the good and the bad -- and I believe his speech will come to represent an important step forward in race relations in our country," Biden said.
Obama advisers said he wrote the deeply personal speech himself. They said it was delivered in Philadelphia because of the city's historical significance, not because it is the most populous black city in Pennsylvania, site of the next primary vote on April 22.
Obama said he came to Wright's church, Trinity United Church of Christ in Chicago, nearly 20 years ago because he was inspired by the pastor's message of hope and his inspiration to rebuild the black community. He also said black anger persists over injustice in America, and whites shouldn't be surprised that it bursts out in sermons.
"The fact that so many people are surprised to hear that anger in some of Reverend Wright's sermons simply reminds us of the old truism that the most segregated hour in American life occurs on Sunday morning," he said.
"In the white community, the path to a more perfect union means acknowledging that what ails the African-American community does not just exist in the minds of black people; that the legacy of discrimination -- and current incidents of discrimination, while less overt than in the past -- are real and must be addressed," Obama said.
Obama said it's not just blacks who are angry -- some whites are, too, because they feel blacks are often given an unfair advantage through affirmative action.
"When they are told to bus their children to a school across town, when they hear that an African-American is getting an advantage in landing a good job or a spot in a good college because of an injustice that they themselves never committed, when they're told that their fears about crime in urban neighborhoods are somehow prejudiced, resentment builds over time," he said.
"If we walk away now, if we simply retreat into our respective corners, we will never be able to come together and solve challenges like health care or education or the need to find good jobs for every American," Obama said, drawing a rare burst of applause in a somber address.
The Rev. Jesse Jackson, who until Obama had been the black candidate closest to winning a major party's presidential nomination, said video of Wright's sermons had threatened to derail the campaign with racial fear -- along with comments made by Clinton supporter Geraldine Ferraro that Obama wouldn't have gotten so far in the campaign if he were white.
Jackson said of Obama, "He made the case we've been here before, but not this time will we linger. This time we're going to higher ground."