John the Apostle, according to the New Testament, was the son of Zebedee, and the brother of James. One tradition gives his mother's name as Salome. They originally were fishermen with their father in the Lake of Genesareth. He was first a disciple of John the Baptist, then a disciple of Jesus Christ, and later was named one of the twelve Apostles.

John is traditionally held to be the author of five books of the New Testament: The Gospel bearing his name, the three epistles bearing his name, and the Book of Revelation (the Revelation of Jesus Christ).

Roman Catholic and Eastern Orthodox tradition says that he and Mary (the mother of Jesus) moved to Ephesus, where both eventually died. Many scholars question this, especially due to the advanced age which Mary would have reached by this time. Some believe, however, that there is support for the idea that John did go to Ephesus and from there wrote the three epistles attributed to him. John also was allegedly banished by the Roman authorites to the Greek island of Patmos, where it is believed he wrote the Book of Revelation around A. D. 95. Some believe his tomb is located at Sel├žuk, a small town in the vicinity of Ephesus.

It is generally believed that in his later years John mentored Polycarp, who later became Bishop of Smyrna. The Roman Catholic Church also associates Ignatius of Antioch with him.