Andrew Scalley played lacrosse for his final two years at high school Archbishop Spalding, earing the Adidas All-American honors his junior season, and notching 35 points his senior season.
At Mount St. Mary's, Scalley continued his lacrosse scholastic career while majoring in business. His freshman season he was named the Northeast Conference Rookie of the Year upon finishing with 32 goals and 17 assists. As a sophomore, Scalley was named First Team All-Northeast Conference after posting 38 goals and 14 assists, and recorded at least one point in all games played at the Mount. Halfway through his collegiate career he had collected 28 groundballs, had caused four turnovers, and led the team with eight extra-man goals. His junior year, he continued to improve, eventually leading the team with 53 points (29 goals and 24 assists).