Richardson finished his 7 season career with 20 interceptions, which he returned for 247 yards and a touchdown. He also recorded 4 fumble recoveries. Known as "L.A. Mike", he was a featured soloist of the "Shuffling Crew" in the Super Bowl Shuffle video in 1985.
In 2008 Richardson faced a 13-year sentence for possession of methamphetamine and crack cocaine. It was his twenty first drug conviction since the end of his football career. Former teammate Richard Dent and coach Mike Ditka both supported Richardson being sent to a rehab facility rather than prison. The judge ultimately sentenced Richardson to a year in prison and an extended probation period, violation of which would result in Richardson serving the remainder of a 13-year sentence.