Learn more about Zadok from the Easton’s Bible Dictionary

Righteous. (1.) A son of Ahitub, of the line of Eleazer (2 Sam. 8:17; 1 Chr. 24:3), high priest in the time of David (2 Sam. 20:25) and Solomon (1 Kings 4:4). He is first mentioned as coming to take part with David at Hebron (1 Chr. 12:27, 28). He was probably on this account made ruler over the Aaronites (27:17). Zadok and Abiathar acted as high priests on several important occasions (1 Chr. 15:11; 2 Sam. 15:24-29, 35, 36); but when Adonijah endeavoured to secure the throne, Abiathar went with him, and therefore Solomon "thrust him out from being high priest," and Zadok, remaining faithful to David, became high priest alone (1 Kings 2:27, 35; 1 Chr. 29:22). In him the line of Phinehas resumed the dignity, and held it till the fall of Jerusalem. He was succeeded in his sacred office by his son Azariah (1 Kings 4:2; comp. 1 Chr. 6:3-9).
(2.) The father of Jerusha, who was wife of King Uzziah, and mother of King Jotham (2 Kings 15:33; 2 Chr. 27:1).
(3.) "The scribe" set over the treasuries of the temple by Nehemiah along with a priest and a Levite (Neh. 13:13).
(4.) The sons of Baana, one of those who assisted in rebuilding the wall of Jerusalem (Neh. 3:4).