Gregory was born to a Gallo-Roman senatorial family of the Auvergne. Educated by his uncle St. Gallus of Clermont and by St. Avitus, he was elected bishop of Tours in 573. He governed the see of St. Martin for twenty-one years through the bloody and turbulent reigns of the warring Merovingian kings — Sigebert, Chilperic, Brunhild, Fredegund — whose violence forms the dark backdrop of his great chronicle.
His Historia Francorum ('History of the Franks') in ten books is the principal source for our knowledge of 6th-century Gaul and the Christianization of the Merovingian kingdom. His seven Books of Miracles record the miraculous histories of the cult of St. Martin and of other Gallic saints — the source of much of our knowledge of the local cults of early medieval France.
He was a great patron of the basilica of St. Martin at Tours, which under his governance became the principal pilgrim destination in early medieval France. His own tomb beside it was for centuries a secondary pilgrim site.