Modern historians, including Claus Krag, assume that his rule may have been limited to the coastal areas of western and southern Norway.

Many Norwegian chieftains who were wealthy and respected posed a threat to Harald; therefore, they were subjected to much harassment, prompting them to vacate the land.

In following centuries, the kingdom was variously ruled, wholly or in part, by descendants of King Harald or by earls under the suzerainty of Denmark.

The tale begins with a marriage proposal that resulted in rejection and scorn from Gyda, the daughter of Eirik, king of Hordaland.

Harald was therefore induced to take a vow not to cut nor comb his hair until he was sole king of Norway, and that ten years later, he was justified in trimming it; whereupon he exchanged the epithet "Shockhead" or "Tanglehair" for the one by which he is usually known.