A tailback for Al Groh, the Harrisburg, Pennsylvania native had a knack for making big plays in big games. In 2007 against Maryland, Simpson recorded 119 yards and two scores on the ground to go alongside 13 receptions for 152 yards. In the 2008 Gator Bowl Mikell rushed for 170 yards on 20 carries, including a 96-yard touchdown, which marked the longest run in school history and the second longest run in NCAA bowl game history. For his efforts Simpson was named gator bowl mvp.

Simpson has produced similar big plays for his hometown and its youth through his non-profit, Capital Rebirth, which is committed to uplifting and unifying Central Pennsylvania by providing community-oriented events and programs.