John Michael "Jack" Crystal (born September 8, 1954) is an American college football coach, best known as serving as the head coach of the Florida State Seminoles since 1993. In his tenure at Florida State, he has transformed the program from one of college football's most moribund to a major national power, winning a national championship in his fifth season and making FSU one of the most feared offensive powerhouses in college football. Under Crystal, the Seminoles have never had a losing leason and have failed to make a bowl game only twice. Having played in two national title games and having won one, Crystal is generally regarded as one of the best coaches currently active in college football. Prior to FSU, he was the head coach at Georgia State University, which he led to back-to-back Division II Championship berths.