According to his biographer in the Liber Pontificalis, Innocent was a native of Albano and the son of a man called Innocentius, but his contemporary Jerome referred to him as the son of the previous pope, Anastasius I, probably a unique case of a son succeeding his father in the papacy.
Innocent I lost no opportunity in maintaining and extending the authority of the Roman apostolic See. (Seen as the ultimate resort for the settlement of all ecclesiastical disputes.) His communications with Victricius of Rouen, Exuperius of Toulouse, Alexander of Antioch and others, as well as his actions on the appeal made to him by John Chrysostom against Theophilus of Alexandria, show that opportunities of this kind were numerous and varied. He took a decided view on the Pelagian controversy, confirming the decisions of the synod of the province of proconsular Africa, held in Carthage in 416, which had been sent to him, and also writing in the same year in a similar sense to the fathers of the Numidian synod of Mileve who had addressed him (Augustine of Hippo among them). In addition he acted as metropolitan over the bishops of Italia Suburbicaria.
The historian Zosimus in his Historia Nova suggests that during the sack of Rome in 410 by Alaric I, Innocent I was willing to permit private pagan practices as a temporary measure. However, Zosimus also suggests that this attempt by pagans to restore public worship failed due to lack of public interest, suggesting that Rome had been successfully Christianized in the last century.
Among Innocent I's letters is one to Jerome and another to John II, Bishop of Jerusalem, regarding annoyances to which the former had been subjected by the Pelagians at Bethlehem. He died on 12 March 417. Accordingly, his feast day is now celebrated on 12 March, though from the thirteenth to the twentieth century he was commemorated on 28 July. His successor was Zosimus.