Gregory of Antioch began as a monk in the monastery of the Byzantines in Jerusalem, or so we learn from Evagrius Scholasticus. He was transferred by the emperor Justin II (565-578 ) to Sinai. He was abbot there when the monastery was attacked by Arabs. John Moschus mentions he was also abbot of Pharan in Palestine. In 569-70 he became Patriarch of Antioch after Justin II deposed the Patriarch Anastasius. Gregory was an influential figure, who quarrelled with the Count of the East and was subjected to official harassment and “enquiries” in consequence, including a appearance in court in Constantinople some time before 588. The charges were trumped up, it seems, and he was acquitted. When Roman troops fighting the Persians mutinied in the time of the emperor Maurice, Gregory was asked to mediate. When Chosroes II of Persia was obliged to flee to the Romans for safety early in his reign, Gregory of Antioch and Domitian, metropolitan of Melitene, were sent to meet him. His services were evidently acceptable; when Chosroes regained his kingdom, he sent Gregory the cross which had been earlier carried off from Sergiopolis by Chosroes I. After this, Gregory made a tour of the border lands to convert Monophysites to the Chalcedonian definitions. He died in 593-4 from taking a drug, intended to relieve gout. His predecessor Anastasius then become Patriarch once more.
A small number of homilies have reached us, mostly under other names, which are also extant in various oriental languages. He seems to have been a gifted speaker. Three of these homilies (CPG 7385-7) were preached on successive Sundays. The address to the army or oratio ad exercitum (CPG 7388) preserved in Evagrius Scholasticus seems to be by Evagrius himself. Finally there is a homily on the first martyr, Stephen (CPG 7389) extant only in Georgian, which is perhaps a letter rather than a sermon.
The homilies can be found in PG 10, 1177-89; PG 61, 761-4; PG 88, 1848-66; and PG 88 1872-84. The homily of Stephen is in PO 19 (1926) 689-99, with an encomium following in 699-715.