He ruled Oldtown and the Hightower for a short time following his father's death, during the Second Greyjoy Rebellion.
Following the War of the Split Stag, Young Garth was betrothed to Merianne Tyrell, the eldest child of Lord Theodore Tyrell. The union was hoped to reunite the houses that had fought on opposite sides in the civil war.
While trying to save his younger brother during the Greyjoy uprising, Garth was struck in the spine with a throwing ax and returned to Oldtown a cripple. His brother, Gavyn died in the battle, whilst his father died near the start of the war.
Shortly after returning to Oldtown and becoming the lord, Garth died. Many say he committed suicide although others have their doubts. His youngest brother, Gylen Hightower assumed the lordship and title, Voice of Oldtown, mere days after Garth's death.Garth never married and had no children to challenge the claim.