Harald Greycloak was the son of Eirik Bloodaxe and a grandson of Harald Fairhair. His mother was Gunnhild Gormsdatter, the sister of King Harald Bluetooth. After his father"s death in 954, Harald and his brothers allied with their grandfather, King Harald Gormson, against King Haakon I of Norway.
They fought several battles against King Haakon including the Battle of Rastarkalv near the island of Frei in 955 and the Battle of Fitjar in 961. Harald, by being the oldest, was the most powerful of the brothers. Harald moved to strengthen his rule by killing the local rulers including Sigurd Haakonsson, Tryggve Olafsson and Gudrød Bjørnsson.
Harald Greycloak thus took power over the country up to and including Hålogaland.
Harald established control over the trade route along the Norwegian coast. He also undertook a Viking expedition to Bjarmaland, today the area of Arkhangelsk in northern Russia.
Harald soon became less dependent on support from Harald Bluetooth. The surviving brothers of Harald Greyhide fled the country after his death.
