He came from Samnium, the son of one Castorius. Following the death of Pope John I at the hands of the Ostrogoth King Theodoric the Great, the papal voters gave in to the king's demands and chose Cardinal Felix as Pope. Felix's favor in the eyes of the king caused him to push for greater benefits for the Church.
He was elected after a gap of nearly two months after the death of John I. During his reign, an Imperial edict was passed granting that cases against clergy should be dealt with by the Pope. He defined church teaching on grace and free will in response to a request of Faustus of Riez, in Gaul, on opposing Semi-Pelagianism.
Felix attempted to designate his own successor: Pope Boniface II. The reaction of the Senate was to forbid the discussion of a pope’s successor during his lifetime or to accept such a nomination. The majority of the clergy reacted to Felix's activity by nominating Dioscorus as Pope. Only a minority supported Boniface.
When regnal numbering of the Popes began to be used, Antipope Felix II was counted as one of the Popes of that name. The second true Pope Felix is thus known by the number III, and the true third Pope Felix was given the number IV. This custom also affected the name taken by Antipope Felix V, who would have been the fourth Pope Felix.