His father was Macnia mac Lugdach, and his mother was Sadb ingen Chuinn, daughter of the former High King Conn Cétchathach.
Spending a number of years in exile, made an alliance with Benne Brit, son of the king of Britain, raised an army of foreigners, and returned to Ireland.
He ruled for thirty years until he was driven from the throne by Art's son Cormac after he gave a false judgement on Bennaid, a female hospitaller, whose sheep had illegally grazed on the queen's woad.
Cormac was unable to take the throne directly, being forced to flee to Connacht by the king of Ulster, Fergus Dubdétach, who held the High Kingship for a year after Lugaid's death.
Modern descendants of Lugaid mac Con include the O'Driscolls, O'Learys, Coffeys, Hennessys and Flynns of County Cork.