He was the eldest son of Count William II of Angoulême and Gerberga of Anjou.
However, a twelfth century chronicler believed that Alduin's wife Alaisia poisoned Count William.
His accession as Count of Angoulême was immediately contested by his younger brother Geoffrey, quarreling over the inheritance of Blaye castle.
He was married to Alaisia, the heiress of Viscount Grimoard of Fronsac and his wife Dea of Montignac.
He was succeeded by his brother Geoffrey, who ousted Alduin's children from the throne of Angoulême.