Clarke served as Professor Emeritus of the History and Sociology of Religion at [[King's College, University of London]], having taught there from 1994 to 2003, the Director of the Centre for New Religions at King's College, and a professorial member of the Faculty of Theology at the [[University of Oxford]] (since 2003); earlier in his career (1974–1978) he was Professor of African History at the [[University of Ibadan]], [[Nigeria]].<ref name=debretts /><ref>Sundermeier, Theo. ''The individual and community in African traditional religions'', LIT Verlag, ISBN 978-3-89473-937-9</ref>
Clarke inaugurated a series of annual conferences on new religious movements at King's, which brought together academics from a variety of backgrounds. These conferences eventually evolved into the "INFORM" (Information Network Focus on Religious Movements) seminars.
