...after being convicted of 24 felony counts of mail fraud, wire fraud, and racketeering.

 
He WAS in prison but he had his sentence commuted by Trump at the request of...wait for it...Diamond and Silk.
http://www.businessinsider.com/kwame-kilpatricks-pardon-sponsored-by-diamond-and-silk-2021-1

 
Here they are getting in Trump's face and telling him: "You better let Kwame out!!"