Harvey took the unexpected call during the taping of an episode celebrating his 56th birthday last week.
When the man appeared via satellite and wished Harvey a happy birthday, the comedian was visibly surprised and replied, "Aw, man," as he walked back and forth across the stage, trying to regain control of his emotions.
"This is Rich Liss from Orlando, Florida," the man said. "Do you still love me, baby?"
Harvey choked back tears, then told the caller, "Hey, man, I love you."
The talk-show host then explained to the crying audience how Liss and his wife, Becky, were huge supporters of his when he was a carpet cleaner trying to begin his comedy career three decades ago.
"I was struggling," Harvey said, wiping tears from his eyes. "I didn't have nothing. And these people ... took me in. ... I never forgot it. Thank you. I love you all."
Harvey said he had looked for the couple for years in an effort to repay their kindness, but couldn't find them.
"I got money now, Rich," he said, promising he would send a plane to bring Liss and his wife to Chicago for a taping of his show.