St. Louis graduated as the top tight end receiver in Bears' football history. He was a four-year letterman, and three-year starter, from 1996 to 1999. He closed his playing career with 93 catches for 1,074 yards and seven touchdowns, becoming the first Bears tight end to reach the 1,000-yard receiving mark. St. Louis played for the Bears under coach Del Miller for three seasons and coach Randy Ball for one year. In 1999, St. Louis earned Football Gazette Football Championship Subdivision All-America honors to go with three Missouri Valley Football Conference all-league first team selections for his receiving and blocking skills. He was the first Bear to play in two postseason all-star games, competing in the East–West Shrine Game and the Hula Bowl following his senior season.