[1][2][3] Antony was of undistinguished background, but received a good education, becoming a lawyer in Constantinople in c. 800.

The emperor appointed him a member of the committee headed by the future Patriarch John VII of Constantinople to find patristic support for Iconoclasm.

In 821, the new Emperor Michael II appointed Antony patriarch, disappointing the monastery of Stoudios, who were hoping that icons would be restored.

When the patriarch of Antioch crowned Thomas the Slav rival emperor, Antony I had him excommunicated in 822.

The iconodule historians record that Antony I was stricken with a wasting disease as divine punishment for his participation in Iconoclast councils.