[2] At a young age he was raised at the Lateran Palace during the pontificate of Adrian I, and it was under Leo III that he was ordained a subdeacon before he was subsequently made a deacon.
Very popular among the Roman people,[3] within ten days of Leo III's death, he was escorted to Saint Peter's Basilica and consecrated bishop of Rome on or about 22 June 816.
[6] At Mass on Sunday, 5 October 816, Stephen anointed Louis as emperor, placing a crown on his head that was claimed to belong to Constantine the Great.
[10] They also renewed the pact between the popes and the kings of the Franks, confirming the privileges of the Roman church, and the continued existence of the recently emerged Papal States.
[11] Stephen also raised Bishop Theodulf of Orléans to the rank of archbishop, and had Louis release from their exile all political prisoners originally from Rome who had been held by the emperor resulting from the conflict that plagued the early part of Pope Leo III's reign.
After holding the traditional ordination of priests and bishops in December and confirming Farfa Abbey's possessions on condition that every day the monks would recite one hundred Kyrie eleison as well as a yearly payment to the Roman Church of ten golden solidi, Stephen died on 24 January 817.