Marcellino was a two-way player for the Crusader football team, starting for two years as a halfback on offense, and for three seasons as a cornerback and safety on defense. He was the leading rusher on the 1963 team with 406 yards, and led the team in all-purpose yards during the 1963 (939 yards) and 1964 (901 yards) seasons. Marcellino was also a receiving threat out of the backfield, catching a team-best 21 passes for 277 yards in 1963, while leading the team in kickoff and punt return yards in both 1963 (256 yards) and 1964 (281 yards). He received the O'Melia Award following the 9-0 victory over Boston College in 1963, after carrying nine times during a 54-yard drive which he ended with a three-yard scoring run. Marcellino received both the Connor Award and the Davitt Award following the 1963 season, and was also a letterwinner on the Crusader lacrosse team.