He was the son of Niall mac Cernaig Sotal (died 701) and great-grandson of the high king Diarmait mac Áedo Sláine (died 665).
He ruled the Uí Chernaig from 724-729 succeeding his brother the high king Fogartach mac Néill (died 724).
His father had been assassinated by the Uí Chonaing king of Brega, Írgalach mac Conaing (died 702) setting off a longstanding feud between these two septs of the Síl nÁedo Sláine.
The more primary source, The Annals of Ulster, do not give him this title however.
This biography of a member of an Irish royal house is a stub.