Innocent was born in Albano, Italy. He lived during the time of Saints Jerome and Augustine. He became Pope, on December 22, 401. Jerome, writing to the virgin Demetrias, says of him: "Hold fast to the faith of holy Innocent, who is the son of Anastasius of blessed memory and his successor in the apostolic throne; receive no strange doctrine, however shrewd and prudent you may think yourself."

During his pontificate, Innocent emphasized papal supremacy, praising the bishops of Africa for referring the decrees of their councils at Carthage and Milevis in 416 that condemned Pelagianism, to the pope for confirmation. This confirmation stirred St. Augustine to pen his famous remark: "Roma locuta, causa finita est" (Rome has spoken, the matter is ended).

Innocent was pope during the capture and sack of Rome by the Goths under Alaric in 410. He condemned the heresies of Pelagius and Celestinus, decreeing that children, even though born of a Christian mother, must be born again by water, in order that their second birth may cleanse away the stain they have contracted by the first. He also approved the observance of fasting on the Saturday in memory of the burial of Christ our Lord. He fought the unjust removal of Saint John Chrysostom and spoke strongly in favor of clerical celibacy. He sat fifteen years, one month, and ten days. Innocent died in Rome, March 12, 417 and was buried in the cemetery called ad Ursum Pileatum.