The son of Elie du Tillet, a mayor and captain of Angoulême under Francis I, he was appointed bishop of Saint-Brieuc in 1553.
Although a Gallican,[1] he took part in the Council of Trent, where he encouraged Gentian Hervet to undertake a Latin translation of Photius' Syntagma together with Balsamon's interpretation from a manuscript which had recently come into his possession.
Tillet also in 1553 obtained in Rome a Hebrew version of St. Matthew's Gospel.
In 1568 he published an edition of works of Lucifer of Caralis against emperor Constantius II.
He had a brother also named Jean du Tillet, with whom he collaborated in scholarship.