Gash was drafted by the New England Patriots in 1992 and played 12 years in the NFL. He was voted to the Pro Bowl in 1998 and 1999. He was cut by the Ravens in 2004 and moved on to coaching the following year with the New York Jets as an assistant running backs coach.
Gash was a part of the Lions coaching staff since 2007, when he signed on as a special teams assistant. He became the Lions running backs coach in 2008, a job he held until December of 2012.