Guy served as the Sun Devils defensive coordinator for four seasons. Guy's 2002 Holiday Bowl defense set school records for sacks and Tackles for Loss (TFLs) with the help of future NFL Super Bowl Champion Terrel Suggs who won the Lombardi and Outland Trophies, thanks in large part to setting the NCAA single season sack record. In 2004, ASU went 9–3 and defeated Purdue in the Sun Bowl. That marked the Sun Devils' second bowl appearance in three years. ASU's defense finished that year ranked 28th nationally in rushing defense, 32nd in pass efficiency defense and 48th in both total and scoring defense. Guy left Arizona State in 2005, returning to Utah State to become the head coach. Between 2005 and 2008, Guy led the Aggies to a 9–38 record. During his tenure, the team failed to win more than three games in any of his four seasons. Following his firing at USU, he was the linebackers coach at Louisville (2009) and UNLV (2010).