[3] He was elected pope by popular acclamation on 11 February 731, but was not formally consecrated as bishop of Rome until 18 March,[4] after having received the approval of the Byzantine exarch of Ravenna.

[10] He ordered to be erected in the heart of St. Peter's Basilica an iconostasis, situated between six onyx and marble columns which had been sent to Gregory as a gift from the exarch Eutychius.

[13] A temporary lull in the conflict between the Byzantines and the Lombards allowed Gregory to deal with some longstanding internal issues, in particular the ongoing jurisdictional dispute between the patriarchs of Grado and Aquileia.

Gregory approved of the election of his successor, Nothhelm, while in 735 he agreed to the request of King Ceolwulf of Northumbria that Bishop Egbert of York should be elevated to the rank of archbishop.

He also refortified Centumcellae, purchasing from Thrasimund II of Spoleto the fortress of Gallese along the Via Flaminia, which had been taken by the Lombards, interrupting Rome's communications with the exarch at Ravenna.

[22] In that same year,[23] Liutprand demanded that the Lombard dukes of Spoleto and Beneventum ravage the area around the Duchy of Rome; but both refused, citing a treaty with the pope.

[26] Although Gregory stated that he was willing to give up his allegiance to the Eastern Empire and place himself under the protection of the Franks, Charles made no promise to assist, since he was fully occupied by the Umayyad invasion of Gaul.

[29] The Lombard capture of the towns of Ameria, Ortas, Polimartium and Blera once again caused Gregory to write to Charles, this time in even greater tones of despair, beseeching his aid:[30] Our affliction moves us to write to you once again, trusting that you are a loving son of St. Peter and of us, and that, from respect for him, you will come and defend the Church of God and His peculiar people, who are now unable to endure the persecution and oppression of the Lombards.

[31]This time Charles Martel did send an embassy to Rome, and this implicit support, together with the beginnings of fever running through his troops, forced Liutprand to march back to Pavia by the end of August 739.

[33] Learning that Charles Martel was sick, Liutprand once again returned to attacking the Exarchate in 740, forcing Gregory yet again to appeal to the Franks, who again refused to become involved.