John II, was pope from 533 - 535. His name at birth was Mercurius, and was the son of Projectus, born in Rome on the Caelian Hill. He was made pope January 2, 533.

He was the first pope to adopt a new name (regnal name) upon elevation to the papacy, as his birth name was the name of the Roman god Mercury. At the outset of his pontificate, John II secured from Athalaric, king of the Ostrogoths in Italy, confirmation of the decree against simony (the purchase or sale of church offices or preferment) that had been issued by the Roman Senate. The following year John obtained a profession of orthodox faith from the Byzantine emperor Justinian I the Great, a significant accomplishment in light of the strength of Monophysitism in the Byzantine Empire at that time.

The Liber Pontificalis records that he received a personal profession of faith from Justinian, as well as valuable gifts. He died May 8, 535.