His first patriarchate was long compared to the usual length of his office in that century, and Jeremias III succeeded to cope with two attempts of deposition, probably sprung from his support to the Russian Tsardom, on 1 January 1718 the Metropolitan of Pruoza, Cyril, was elected Patriarch in his place, but Jeremias III returned on the throne next 17 January, and in 1720 he was arrested and his rival, the previous Patriarch Cyril IV of Constantinople, reigned from 10 to 22 January, when Jeremias III was re-installed.

In 1732, Jeremiah III returned from exile and on 15 September 1732 he was appointed Patriarch for the second time,[3] but after only a few months, in March 1733, he had to leave the throne because he suffered of hemiplegia, and he retired in Great Lavra Monastery on Mount Athos, where he died in 1735.

[4] He also reorganized the Monastery of the Transfiguration on the Princes' Islands, which was enriched with a collection of valuable pictures that had been donated by Peter the Great of Russia.

In December 1723, Jeremias III approved the suppression, made in 1721 by Peter the Great of Russia, of Patriarchate of Moscow and its replacement with the Most Holy Synod.

Jeremias III imposed austerity at the expense of the Patriarchate, thus managing to reduce debt and improve its financial situation.