Born Mac Bethad mac Findláech, he became Mormaer of Moray in 1032 and King of Alba in 1040 after Duncan I fell in battle near Elgin.
Ruled largely peacefully for seventeen years and made a pilgrimage to Rome in 1050, where Marianus Scotus wrote he scattered money to the poor like seed.
Killed at the Battle of Lumphanan in August 1057 by forces backing Duncan's son Malcolm III, and buried on Iona.