Harvey is a computer programmer at a Fortune 100 company in the area and is said to be very involved in the homeless shelters in Nashville.
Harvey's cellphone, car and wallet were found at his home. He was recently diagnosed with a medical condition and his medication was also found at his house.
For the past 36 hours, Harvey's sister, Zina Crowder, has been behind the wheel of her car searching for her brother.
"I've been calling the hospitals to see if any John Does were listed," she said.
In an act of desperation, Crowder decided to post Harvey's picture to Facebook Thursday night to let her friends and family know he was missing.
Almost immediately, people began commenting on her post. Some said they had seen Harvey in several locations.
"The tip yesterday said he looked very disoriented," Crowder said. "He was walking in a manner to where he wasn't picking up his feet, you know, like he was exhausted."
Harvey is 5'5" and weighs 185 pounds. He has long brown hair and a beard and was last seen wearing a plaid shirt and khaki pants. He may be barefoot.
Crowder said her brother is often seen twirling a feather in his hand.
"I truly, when I posted the Facebook post, felt like it was a life or death situation and we needed to find him," Crowder said.
While Harvey still has been found, his family said they had hope.
"I really was prepared for the worst yesterday, until I saw about the sightings," said David Harvey, Michael Harvey's father.
If you see him, police are asking you to call 911.