Although little is known about him, and he appears only in the Books of Chronicles, the Chronicler states that the events of Solomon's reign, as well as Iddo's prophecies concerning the rival king Jeroboam I of Israel were recorded in writing. The alleged records composed by Iddo are no longer extant. He is also credited with a history of King Rehoboam, and a history of his son King Abijah.
A tradition of identifying Iddo as being identical to the unnamed prophet of 1 Kings 13 can be found in the first-century (CE) Jewish historian Josephus, the fourth- and fifth-century Christian commentator Jerome], and the medieval Jewish commentator Rashi. The protagonist of 1 Kings 13 is identified simply as "a man of God." In 1 Kings 13, the unnamed prophet--as Iddo is said to have done elsewhere--prophesies against Jeroboam. After an unfortunate encounter with an older prophet, the "man of God" is killed by a lion as punishment for unwittingly disobeying a divine comment. The older prophet then used his own tomb as a burial place for the "man of God." The Books of Kings record that, 300 years later, during the reign of king Josiah, the king was engaged in the process of burning human bones to ritually defile Jeroboam's altar. During the trip to do so, Josiah noticed the tombstone of the "man of God," and when he asked was told that it was the tomb of the man who had predicted the destruction of Jeroboam's altar. Josiah ordered that the "man of God's" tomb be left unmolested in commemoration of his prophecy.
Another Iddo is mentioned in Ezra 8:17 as the chief man at the place Casiphia. Ezra requests assistance from Iddo and his brethren to bring servants for the Temple. It is this Iddo Ezra refers to when he calls the prophet Zechariah a "son of Iddo" in Ezra 5:1 and 6:14. The Book of Zechariah 1:1 and 1:7 mention Iddo as the paternal grandfather of Zechariah.