He returned, late in 1121, after which he began to subsidize the Templars, maintaining two knights in the Holy Land for a year.

By 1127, Fulk was preparing to return to Anjou when he received an embassy from King Baldwin II of Jerusalem.

Fulk abdicated his county seat of Anjou to his son Geoffrey and left for Jerusalem, where he married Melisende on 2 June 1129.

The other Crusader states to the north feared that Fulk would attempt to impose the suzerainty of Jerusalem over them, as Baldwin II had done.

In 1132, she allied with Pons of Tripoli and Joscelin II of Edessa to prevent Fulk from marching north.

Author and historian Bernard Hamilton [pl] wrote that Fulk's supporters "went in terror of their lives" in the palace.

Contemporary author and historian William of Tyre wrote of Fulk: "He never attempted to take the initiative, even in trivial matters, without (Melisende's) consent."

As regent, he had Raymond of Poitou marry the infant princess Constance of Antioch, his and Melisende's niece.

In 1137, Fulk was defeated in battle near Baarin but allied with Mu'in ad-Din Unur, the vizier of Damascus.

Fulk captured the fort of Banias, to the north of Lake Tiberias and thus secured the northern frontier.

To help give the kingdom access to the Red Sea, Fulk had Blanchegarde, Ibelin, and other forts built in the south-west to overpower the Egyptian fortress at Ascalon.

This city was a base from which the Egyptian Fatimids launched frequent raids on the Kingdom of Jerusalem and Fulk sought to neutralise this threat.

[3] His horse stumbled, fell, and Fulk's skull was crushed by the saddle, "and his brains gushed forth from both ears and nostrils", as William of Tyre describes.

According to William of Tyre, Fulk was "a ruddy man, like David... faithful and gentle, affable and kind... an experienced warrior full of patience and wisdom in military affairs."

Ibn al-Qalanisi, who calls him al-Kund Anjur, an Arabic rendering of "Count of Anjou", says that "he was not sound in his judgment nor was he successful in his administration."