The Marist Brothers built this College to provide a Catholic Education to the boys of Eastern Metropolitan Melbourne. Marcellin College therefore has a very close association with local Catholic Parishes and associated Catholic Primary Schools in supporting the continued faith development of boys. This association strongly influences the Colleges enrolment criteria in that Catholic boys who live within the boundaries of the Colleges designated feeder parishes are given priority of entry. These parishes are:
| Alphington | St. Anthony’s | Heidelberg West | St. Pius X |
| Balwyn North | St. Bede’s | Ivanhoe | Mary Immaculate |
| St. Bernadette’s | |||
| Box Hill | St. Francis Xavier | ||
| Kew East | St. Anne’s | ||
| Bulleen | St. Clement of Rome | ||
| Macleod | St. Martin of Tours | ||
| Deepdene | Our Lady of Good Counsel | ||
| Montmorency | St. Francis Xavier | ||
| Doncaster | St. Gregory the Great | ||
| Eltham North | Holy Trinity | ||
| Donvale | Our Lady of the Pines | ||
| Park Orchards | St. Anne’s | ||
| Eltham | Our Lady Help of Christians | ||
| Surrey Hills | Our Holy Redeemer | ||
| Greythorn | St. Bridget’s | ||
| Templestowe | St. Kevin’s | ||
| Heidelberg | St. John’s | St. Charles Borromeo |