Rǫgnvaldr was a son of Guðrøðr Óláfsson, King of Dublin and the Isles, and a member of the Crovan dynasty. In the mid twelfth century, Guðrøðr Óláfsson inherited the kingship of the Isles, a region comprising the Hebrides and Mann. He soon faced internal opposition from his brother-in-law, Somairle mac Gilla Brigte, Lord of Argyll, who seized the Inner Hebridean portion of the kingdom in 1153. Three years later, Somairle seized the entire kingdom, and ruled the entirety of the Isles until his death in 1164. Although Guðrøðr Óláfsson regained the kingship, the territories lost to his brother-in-law in 1153 were retained by the latter's descendants, the Meic Somairle (or Clann Somairle).