Guerrieri started out his coaching career as a graduate assistant for Lenoir–Rhyne for one season. After that Guerrieri would head to Duke as a graduate assistant. After three years as a graduate assistant for Duke, Guerrieri would be promoted to coach the safeties for Duke. Then after coaching the safeties for three years, Guerrieri would get his first shot as a coordinator, as he was promoted be the co-defensive coordinator and safeties coach for Duke. After coaching a total 10 years for Duke, he would leave for Ohio State to be a senior advisor and analyst for the Buckeyes. After one year with the Buckeyes, Guerrieri would be hired as the co-defensive coordinator and safeties coach for the Indiana Hoosiers. After one season with the Hoosiers, Guerrieri returned to the Buckeyes to become the safeties coach.