Upon his fathers death in 839 he became king of Dalriada styled "Cinaed, son of Alpin" and also king of Scots due to the fact that the Hebrides - Argyll were important parts of the land at the time. At this time the Picts were conquered by Vikings with Bridei VI of Pictland being defeated, and Kenneth was set to become the next monarch. Although it wasn't until 843 he became king of the now united Pictish & Scottish tribes. There has also been some evidence he did not become king until 848 although it is pretty unclearnd historically.