Deceased by April 1374. He appears as κῦρ, οἰκεῖος of the Serbian Emperor Stefan Uroš IV Dušan and the Byzantine Emperor Ioannes V. Palaiologos in the sources. He was in charge of Megas Drungarios τοῦ στόλου, 1344. Eparchos, 1348–1350. Megas Primikerios, 1366. Megas Konostaulos, 1367–1374. He was married to Xene Isarina. He had two sons (Michael Angelos Isaris and Theodoros Komnenos Isaris). His son-in-law was Georgios Stanisas. He was a wealthy landowner, who possessed several estates around Thessalonica. He was probably the student of Georgios Akindynos. He also corresponded with him. He was a supporter of the anti-Palamite party. When he turned his coat, he was criticized by Georgios Akindynos as a traitor. He was among the witnesses to the charter of protovestiarites Ioannes Dukas from September 1344, who rejected the claim of the revenue office on the part of the place Diabolokampos, a property of the Docheiariu Monastery. He joined in summer 1345 the proponents of the Byzantine Emperor Ioannes VI Kantakuzenos. He was nearly killed during the revolt of the Zealots. He met Gregorios Palamas on Moun Athos between September 1347 and September 1348. The Serbian Emperor Stefan Uroš IV Dušan donated in April 1348 the dependant peasants in the area of Hermelia, which belonged to Georgios Isaris. The Byzantine Emperor Ioannes V. Palaiologos gave in December 1350 several landed estates to Demetrios Kokalas in addition to his oikonomia. He mandated Georgios Isaris with Manuel Chageres to execute the task. He had a 11 years lasting quarrel with the Hilandar Monastery. He required the sum, which Georgios Stanisas, his son-in-law, paid in order to obtain adelphata. When Stanisas died, Isaris tried to get the money of his son-in-law back. He did not even hesitate to forge documents related to the affair. He was a friend of Makarios Chumnos and probably sponsored his foundation of Nea Moni in Thessalonica.