Eystein was son of King Eysteinn Haraldsson. His nickname Møyla means maiden, girl, cute woman. His father was king of Norway from 1142 to 1157, ruling as co-ruler with his brothers, Inge Haraldsson and Sigurd Munn. Eystein II was killed in 1157 during the power-struggle against his brother, Inge, in an early stage of the civil war era in Norway. After the death of Eystein II, his supporters first rallied around the young Haakon the Broadshouldered, Sigurd Munn's son and Eystein's nephew. Haakon was defeated and killed by Jarl Erling Skakke at Sekken near the town of Veøya in Romsdalen during 1162.