"We have all made mistakes. We have all erred, and we ought not try to sugar coat when we err," Sharpton told a gathering of the Southern Christian Leadership Conference in this New Orleans suburb.
"But we should not throw away everything when we err, and to say that Rev. Jackson made a mistake is correct, but to act like Rev. Jesse Jackson is not pivotal to our movement, our history ... is wrong."
"Jesse Jackson," he added, "is somebody."
Jackson had been scheduled to address the SCLC's 50th anniversary convention Tuesday morning, but his press office said he was on vacation and a representative was sent in his place.
Jackson apologized twice earlier this month for "regretfully crude" comments about Obama during what he thought was a private conversation during a taping break for the news show "Fox & Friends."
In a fiery speech that was part political rally and part big tent revival, Sharpton applauded Obama's success and promised to do what he could to get him elected.
But he also said there is room for more than one leader in the ongoing fight for civil rights.
He called the Illinois senator a product of the civil rights movement - not the end to it.
"The bias in the media is they try to act like we can't have multiple strategists," Sharpton said. "We have never had a one-man movement."
Sharpton urged the group not to forget the history of their movement and to stay involved.
Even the election of Obama would not constitute "achievement of the dream," Sharpton said, because inequality would remain in health care, education and criminal justice.
He said a long fight was waged to get blacks the right to vote and now it is imperative to "protect this vote."
"This vote is soaked in the blood of our martyrs," he said.
