He acceded to power in a coup against his own father, Giorgi IV Dadiani, and came to dominate western Georgian politics by asserting tutelage over King Alexander V of Imereti until being murdered by Ottoman agents.
In 1704, Giorgi made his eldest son, Katsia, prince of Mingrelia and installed Bezhan as lord of Lechkhumi, of which he had dispossessed his younger brother, Iese.
Giorgi returned as prince of Mingrelia after Katsia's death in 1710, but his renewed authority was challenged by Bezhan, who enjoyed support of King George VII of Imereti.
While Bezhan dominated western Georgia, an Ottoman force was stationed in the Imeretian capital of Kutaisi, and Alexander was relegated to managing just his crown estates.
He had his brother Manuchar cast in prison and another, Bishop Gabriel of Chqondidi, defrocked once this corrupted and slave-trading cleric became involved in intrigues against Bezhan and Alexander.