His place and date of birth is unknown. Upon succeeding St. Silvius as bishop, he completed the Basilique St-Sernin, begun by his predecessor. St. Jerome praises him for his munificence to the monks of Palestine, Egypt, and Libya, and for his charity to the people of his own diocese, who were then suffering from the attacks of the Vandals, Alans, and Suevi. For the sake of the poor in his diocese he even sold the altar vessels and so was compelled to carry the Sacred Offering in an osier basket and the Precious Blood in a vessel of glass. In esteem for his virtues and in gratitude for his gifts, St. Jerome dedicated to him his Commentary on Zacharias.
Exuperius is best known in connection with the Canon of the Sacred Scriptures. He had written to Innocent I for instructions concerning the canon and several points of ecclesiastical discipline. In reply, the pope honoured him with the letter Consulenti tibi, dated February, 405, which contained a list of the canonical scriptures as we have them to-day, including the deuterocanonical books of the Catholic Canon. The assertion of non-Catholic writers that the Canon of Innocent I excluded the Apocrypha is not true, if they mean to extend the term Apocrypha to the deuterocanonical books.
The opinion of Baronius, that the bishop Exuperius was identical with the rector of the same name, is quite generally rejected, as the rector was a teacher of Hannibalianus and Dalmatius, nephews of Constantine the Great, over a half a century before the period of the bishop. From Jerome's letter to the Furia of Rome, in 394, and from the epistle of St. Paulinus to Amandus of Bordeaux, in 397, it seems probable that Exuperius was a priest at Rome, and later at Bordeaux, before he was raised to the episcopate, though it is possible that in both of these letters reference is made to a different person. Just when he became bishop is unknown. That he occupied the See of Toulouse in February, 405, (as is evident from the letter of Innocent I mentioned above) and from a statement of St. Jerome in a letter to Rusticus it is certain that he was still living in 411. It is sometimes said that St. Jerome reproved him, in a letter to Riparius, a priest of Spain, for tolerating the heretic Vigilantius; but as Vigilantius did not belong to the diocese of Toulouse, St. Jerome was probably speaking of another bishop.
Exuperius was early venerated as a saint. Even in the time of Gregory of Tours he was held in equal veneration with Saint Saturninus. His feast occurs on 28 September. The first martyrologist to assign it to this date was Usuard, who wrote towards the end of the 9th century.