He copied the way of life of the kings of Israel, marrying into the Ahab family and continuing the Ahab line of sin - from God's point of view, an evil man living an evil life.
But despite that, because of his servant David, God was not ready to destroy Judah. He had, after all, promised to keep a lamp burning through David's descendants.
During Jehoram's reign, Edom revolted against Judah's rule and set up their own king.
Jehoram responded by taking his army of chariots to Zair. Edom surrounded him, but in the middle of the night he and his charioteers broke through the lines and hit Edom hard. But his infantry deserted him.
Edom continues in revolt against Judah right up to the present. Even little Libnah revolted at that time.
The rest of the life and times of Jehoram, the record of his rule, is written in The Chronicles of the Kings of Judah.
Jehoram died and was buried in the family grave in the City of David. His son Ahaziah succeeded him as king.
In the twelfth year of the reign of Joram son of Ahab king of Israel, Ahaziah son of Jehoram king of Judah began his reign.
Ahaziah was twenty-two years old when he became king; he ruled only a year in Jerusalem. His mother was Athaliah, granddaughter of Omri king of Israel.
He lived and ruled just like the Ahab family had done, continuing the same evil-in-God's-sight line of sin, related by both marriage and sin to the Ahab clan.
He joined Joram son of Ahab king of Israel in a war against Hazael king of Aram at Ramoth Gilead. The archers wounded Joram.