Johnson also seemed to hint at Obama's acknowledged youthful drug use, an issue that led another Clinton campaign official to resign. Johnson later denied that was the case.
Clinton was quoted just before the New Hampshire primary as saying King's dream of racial equality was realized only when President Lyndon B. Johnson signed the Civil Rights Act of 1964. Some black leaders have criticized that remark as suggesting Johnson deserved more credit than the slain civil rights leader for the passage and enactment of major civil rights legislation.
While introducing Clinton at Columbia College on Sunday, Johnson criticized Obama's camp.
"That kind of campaign behavior would not be reasonable with me for a guy who says 'I want to be a reasonable, likable, Sidney Poitier,'" said Johnson, owner of the NBA's Charlotte Bobcats. He commented after Clinton said in a televised interview Sunday that she hoped the campaign would not be about race.
Johnson also said Obama's own record should give voters pause.
"To me, as an African American, I am frankly insulted the Obama campaign would imply that we are so stupid that we would think Hillary and Bill Clinton, who have been deeply and emotionally involved in black issues - when Barack Obama was doing something in the neighborhood; I won't say what he was doing, but he said it in his book - when they have been involved," Johnson said.
Obama wrote about his teenage drug use - marijuana, alcohol and sometimes cocaine - in his memoir, "Dreams from My Father."
Johnson later said his comments referred to Obama's work as a community organizer in Chicago "and nothing else. Any other suggestion is simply irresponsible and incorrect," he said in a statement released by Clinton's campaign.
Last month, top Hillary Clinton adviser Bill Shaheen resigned from the campaign after suggesting Democrats should be wary of nominating Obama because his past drug use could be used against him in the campaign.
Obama supporter "I.S." Leevy Johnson, a former South Carolina state legislator, said it was "offensive" that Clinton stood by during Johnson's "personal, divisive attack on Barack Obama."
"For someone who decries the politics of personal destruction, she should've immediately denounced these attacks on the spot," Johnson said in a statement issued by Obama's campaign.
