His birth name was Ioann (, a form of "John"). As a teenager, Ioann knew most of the biblical texts by heart and strove to become a monk. His father, however, insisted that he marry. Once, Ioann asked his father's permission to see his confessor in the Uspensky Monastery in their native town of Staritsa (Tver Oblast). Upon his arrival in 1551, Ioann immediately took monastic vows and assumed the religious name of Job. He spent fifteen years in the cloister and finally became its abbot in 1566 with the help of Ivan the Terrible, who had made Staritsa his residence during the time of the Oprichnina.