He was the son of King David IV the Builder and the Cuman-Kipchak princess Gurandukht, daughter of Khan Otrok.
Vakhtang was involved in an attempted coup against Demetrius I of Georgia, his half-brother and heir apparent.
The 12th-century document The Will of King David contains a vague and controversial passage whereby David instructs the eldest son and heir apparent Demetrius I to rear his younger brother Vakhtang and make him a successor to the throne if the latter proves to be "capable".
A reference to the aristocratic plot against Demetrius on behalf of Vakhtang is found in the contemporaneous Armenian chronicle by Vardan although the author does not directly names the rebellious prince.
This plot, intended to assassinate Demetrius I, was directed by the influential nobleman Ivane Abuletisdze and his son Kirkish.