The baptism of John was not Christian but Jewish. The only faith it had concerning the Messiah was that His coming was close to come. Whoever confessed and repented of their sins and were baptized by John were obedient to his call to "prepare the way of the Lord."
Christianity begins with John the Baptist and he stands right from the beginning in the light of God's plan of redemption. John is himself a part of the gospel of Jesus Christ. John too, like Jesus, is the prophet of the coming kingdom of God.
John's father was a temple priest of Abia, and his mother was one of the daughters of Aaron. John the Baptist and Jesus were cousins. John was only six months older than Jesus, Mary and Elisabeth were with child at the same time. John's parents were really old when John was born and the birth itself was a miracle.
An angel appeared to Zacharias and said, "...you shall have joy and gladness and many shall rejoice at his birth. For he shall be great in the sight of the Lord and shall drink neither wine nor strong drink and he shall be filled with the Holy Ghost, even from his mother's womb. And many of the children of Israel shall he turn to the Lord their God. And he shall go before Him in the spirit and power of Elias, to turn the hearts of the fathers to the children and the disobedient to the wisdom of the just, to make ready a people prepared for the Lord." The angel was just letting us know that the prophecies of Malachi were being fulfilled in John.
Although John came from a family of priests, he never served as a priest, or a scribe, Pharisee or Sadducee.