Kenneth was the brother of Dubh.

In 973 he acknowledged King Edgar of England as his lord in return for recognition that the Scots now held Lothian, which they had seized from the Angles. In about 994, however, he broke his promise to keep the peace and invaded England. He was defeated, and lost Lothian again.

He killed Culen's brother in 977 and was himself killed in 995 in a blood feud at Fettercairn, Kincardineshire by Culen's son, Constantine.