Hvitserk is often seen alongside his brother Ubbe, and likely looks up to him. Having grown up without his father present, Hvitserk has grown resentful and angry. Despite this, he is often seen laughing with his brothers, and seems to be the most lighthearted of them.
As of the Season 2 finale, Hvitserk and his brothers would be known by the Old Norse title of Budlungr or 'prince'.
It is often suggested that Hvitserk is the same individual as Halfdan, another name said to be the son of Ragnar. The Norse sagas name him Hvitserk, while Anglo-Saxon sources refer to a brother named Halfdan, and for this reason historians generally assume they are the same person.
If Hvitserk is the same person as Halfdan, then he was one of the principle leaders of the Danish Mycel Heathen Here (the Great Heathen Army) and assisted with the conquests of Northumbria, East Anglia and the northern half of Mercia. Briefly, between 871-872, Halfdan/Hvitserk would occupy the city of London (then part of the kingdom of Mercia).
The saga The Tale of Ragnar's Sons, which calls him Hvitserk, mentions that he led armies into Gardariki (the Norse term for Russia), where he lost a battle facing overwhelming odds. It claims that he was burnt alive by his captors.
According to the saga Tale of Ragnar's Sons, Hvitserk inherited Jutland (Danish mainland) and Wendland (Luchow-Dannenberg in Lower Saxony) after the death of his father.