Bob Johnson, the former chief executive of BET made what some observers called veiled references to the Illinois senator's admitted drug use as a teenager.
Johnson, a supporter of rival Sen. Hillary Clinton, said he sent Obama an apology letter and also was reaching out by phone, CNN reported.
"Obama accepts the apology. We're going to leave it at that," said Obama spokesman Bill Burton.
Johnson drew criticism following remarks he made Sunday at a campaign stop for Clinton in Columbia, S.C.
The Clinton campaign released a statement from Johnson saying he had been "referring to Barack Obama's time spent as a community organizer and nothing else. Any other suggestion is simply irresponsible and incorrect."
The Obama camp rejected the explanation, CNN said.
"His tortured explanation doesn't hold up against his original statement. And it's troubling that neither the campaign nor Sen. Clinton -- who was there as the remark was made -- is willing to condemn it as they did when another prominent supporter recently said a similar thing," said Burton, before Johnson issued his apology Thursday.