Nothing is known of his personal history, and even the date at which he wrote can be only approximately ascertained as between AD 150 and 270. Jerome's De Viris Illustribus No. 58 speaks of him as "Romae insignis causidicus" [one of Rome's notable solicitors], but in that he is probably only improving on the expression of Lactantius who speaks of him as "non-ignobilis inter causidicos loci" [not unknown among solicitors].
He is now exclusively known by his Octavius, a dialogue on Christianity between the pagan Caecilius Natalis and the Christian Octavius Januarius. Written for educated non-Christians, the arguments are borrowed chiefly from Cicero, especially his De natura deorum ("Concerning the Nature of the Gods"), and Christian material, mainly from the Greek Apologists.
The Octavius is admittedly earlier than Cyprian's Quod idola dei non-sint, which borrows from it; how much earlier can be determined only by settling the relation in which it stands to Tertullian's Apologeticum.
The name Caecilius Natalis contains the nomen Caecilius and cognomen Natilis, that may refer to the gens Caecilia, a plebeian family at Rome.
The name Octavius Januarius contains the nomen Octavius and cognomen Januarius, that may refer to the gens Octavia - the family name of Emperor Augustus.
The name of Marcus Minucius Felix indicate that he was associated with the gens Minucius.