He was the son of Congal mac Áedo Sláine (died 634), a previous king of Brega.
He ruled during a time when his uncles Diarmait mac Áedo Sláine (died 665) and Blathmac mac Áedo Sláine (died 665) were jointly High King of Ireland.
[2] Conaing was slain fighting on the side of Blathmac in this civil war.
Irgalach's son Cináed (died 728) was late High King of Ireland, the penultimate Uí Chonaing High King, the last being Congalach Cnogba in the 10th century.
His daughter Caintigern married Cellach Cualann (died 715), the Uí Máil king of Leinster and was mother of Saint Kentigerna.