While his brothers Basil and Naucratius lived as hermits from , Gregory initially pursued a non-ecclesiastical career as a rhetorician. He did, however, act as a lector. He is known to have married a woman named Theosebia during this period, who is sometimes identified with Theosebia the Deaconess, venerated as a saint by Orthodox Christianity. This is controversial, however, and other commentators suggest that Theosebia the Deaconess was one of Gregory's sisters.
