Rubuta ci gaba ga wannan sakin layi - Maguire ya kasance tauraron dan wasa na makarantar Delbarton, yana taimakawa tawagarsa ta lashe kofin Mennen hudu a jere kuma ta lashe rabon gasar zakarun jihar a matsayin matashi. Bayan kammala karatunsa a 1990, Montreal Canadiens ne suka zaba shi a cikin NHL Draft
sannan ya fara halartar jami'ar Harvard a lokacin kaka. Maguire ya kasance dan wasa mai tsaron gida a kwaleji, yana wasa da abokan hamayya masu tsauri, amma har yanzu yana iya taimaka wa Crimson ya gama saman ECAC Hockey standings shekaru uku a jere. A lokacinsa na ƙarshe, wasan Maguire na kai hari ya rayu kuma ya ninka aikinsa na baya fiye da sau biyu. An kira shi All-American kuma ya tura Harvard zuwa gasar zakarun ECAC da kuma bayyanar a cikin Frozen Four.