Lapidge completed his B.A. at the University of Calgary and taught there for three years after completing an M.A., before going to the University of Toronto in 1967 to begin work on a Ph.D. in the Centre for Medieval Studies. His doctoral dissertation, supervised by Brian Stock, studied the transmission of a nexus of cosmological metaphors, first articulated by Greek Stoic philosophers, to classical and late antique Latin poets, and ultimately to Medieval Latin philosophers and poets of the twelfth century. After completing course-work in Toronto, he went to Cambridge in 1969 to have better access to manuscript depositories while completing his dissertation. The Ph.D. was awarded in 1971. Following a period as a Research Fellow in Cambridge supported by a Killam Senior Research Fellowship, he was appointed Lecturer in the Department of Anglo-Saxon, Norse and Celtic, University of Cambridge in 1974, thereafter progressing to be Reader in Insular Latin Literature and then, in 1991, Elrington and Bosworth Professor of Anglo-Saxon, a chair which he held until 1998. During this time he was able, as Head of Department, to increase the size of the Department and to introduce a number of significant structural changes to its teaching programme. He resigned the Professorship in 1999 in order to become Notre Dame Professor of English at the University of Notre Dame, a position he held until taking early retirement in 2004.
Publications
Lapidge has written or edited more than fifty books and published some 200 articles, on subjects ranging from Greek cosmology and Classical Latin literature to medieval palaeography and textual criticism, especially the literature of Anglo-Saxon England, in both Latin and Old English. He is, for instance, an expert on the Leiden Glossary. He has devoted much of his scholarly energy to editing scholarly journals and series, having been general editor for many years of Anglo-Saxon England, Oxford Medieval Texts, Scriptores Latini Hiberniae, and Henry Bradshaw Society Publications, as well as Compendium Auctorum Latinorum Medii Aevi and Cambridge Studies in Anglo-Saxon England. In 2002, he delivered the Triennial E. A. Lowe Lectures at Corpus Christi College, University of Oxford, speaking on the topic of "The Anglo-Saxon Library"; a revised version of his lectures was published by Oxford University Press.