Osbern was born at Canterbury and brought up by Godric, who was dean from 1058–1080, his term living through the Norman Invasion.
He became a monk, and later precentor of Christ Church, and was ordained by Archbishop Lanfranc of Canterbury (d. 1089).
Eadmer related a story in which the two, in the late 1080s, searched for the relics of Saint Audoen in the crypts of Christ Church, Canterbury.
Upon finding the relics, they were delighted, but the same night, were haunted by "dreadful apparitions".
William of Malmesbury praises the elegance of Osbern's style, but criticises his frequent historical inaccuracies.