Hvitserk was born in the four year gap between Season 2 Episode 1 and 2. Hvitserk is often seen alongside his brother Ubbe, and likely looks up to him. Ubbe flees with Aslaug, Hvitserk, Rollo, Siggy and Helga after Jarl Borg invades Kattegatte. Ragnar eventually returns from England where he is reunited with his family and with the assistance of Lagetha, he takes back Kattegatte.
An older Hvitserk is still seen playing with his brother Ubbe and Sigurd. One day while Aslaug is away and Siggy is watching them Ubbe and Hvitserk wander off onto a frozen lake but Siggy pursues them. She calls out to them despite them knowing she is there Ubbe and Hvitserk ignore her. The ice breaks and Ubbe and Hvitserk fall in. They both nearly drown but Siggy dives in and saves them with the help of Harbard but at the cost of Siggy's life and she drowns.
Ubbe and Hvitserk receive their arm rings from their father so that they can come to Paris with him but not to fight. The Franks then attack the viking camp but Ubbe and the others manage to escape but Helga is wounded. After the Vikings defeat at the hands of Rollo and the Franks they return to Kattegat with the broken and defeated Viking army.
Ten years later after Ragnar disappeared Hvitserk has grown up into a strong and skilled warrior as have all of Ragnar's sons. Having grown up without his father present, Hvitserk has grown resentful and angry at Ragnar. Bjorn brings the news that the Viking settlement in Wessex was destroyed. Hvitserk and his brother discuss why Ragnar didn't tell anyone. Hvitserk then says that if their father ever returned he would kill him, which Sigurd agrees. Ivar gets angry at his brothers for insulting their father and refers them as "Christians" calling them soft. Ragnar then returns to Kattegat after a long absence, a broken man. He then reunites with his sons after ten long years and challenges his sons to kill him (especially Ubbe) so that they can become king. Ragnar provokes Hvitserk to kill him and screams at him to kill him but Hvitserk doesn't move.
None of Ragnar's sons step forward to challenge their father except for Ubbe but instead they just embrace. Ragnar and his sons discuss the lost Wessex settlement and why he came back. Ragnar asks his sons to come to England with him. Hvitserk refuses saying he is sailing with Bjorn to the Mediterranean sea with Harald and Halfdan and Floki. Once Floki's ships are ready Hvitserk travels to Frankia where they try to bargain with his uncle Rollo, who is the Duke of Normandy to let them past his coastline so they can travel to the Mediterranean without any trouble. Hvitserk is introduced to his cousins William, Marcellus and Celsa. However they are imprisoned, but Rollo agrees to let them through as long as he accompanies them. They reluctantly let Rollo come due to his betrayal years earlier but not before knee hauling him for his betrayal.
Hvitserk, Bjorn, Harald, Halfdan, Floki and Rollo then sail down the Mediterranean and arrive in Spain and slaughter any resistance and steal any treasure they could get there hands on. While staring out to the ocean on a cliff Odin himself approachs Hvitserk and Bjorn and tells them their father is dead. Hvitserk and Bjorn return to Kattegat, but not before dropping Rollo back in Frankia. Hvitserk then returns home and finds out that Ubbe has freed Magathe, their lover and is marrying her to his delight and asks Ubbe make sure he doesn't keep her all to himself. After the marriage ceremony Ubbe says that he and Hvitserk can share Magathe since they both love her. Hvitserk, Ubbe and Sigurd then discuss their mothers death but Hvitserk says they shouldn't kill Lathe because he and Ubbe fell through the ice because of her neglect. Ivar says they should but Hvitserk says that Ivar is 'crazy'. Hvitserk and his brothers summon and form the Great Heathen Army to avenge their father. They easily defeat the forces of Northumbria and killing King Alle with a blood eagle ceremony. The Great Heathen Army then faces the force of Wessex, confusing and outmenuvering the forces and causing them to retreat. They capture King Ecbert and High Bishop. Ivar demands a blood eagle for King Ecbert but Ubbe and his brother convince Ivar otherwise. Later Hvitserk watches in horror as Ivar kills Sigurd by trowing an axe into his stomach. Hitserk and Ubbe look at Ivar in anger for killing his own brother, which Ivar shows no remorse.
After Sigurd's death, Hvitserk, Ubbe, and Ivar rule jointly over their newly acquired land in East Anglia. Floki decides to leave the great heathen army to set sail for the unknown, Hivtserk and the army say their goodbyes to Floki. Ivar persuades Hvitserk and Ubbe to go forth and conquer the city of York. Hvitserk and the great heathen army attack take York when the locals were celebrating one of their saints. The attack was a success they easily sacked and occupied the city. After the successful attack and occupation of the city, Hvitserk and Ubbe go to speak with Ivar. They are surprised to see that he now has bodyguards, who initially tried to stop them. Ubbe just stared them down until they stepped aside. They find Ivar getting a large tattoo on to his back, and ask him why he needs bodyguards. "Because I'm a cripple!" he states They ask him why did he not consult them about it and if he thinks he is the leader of the great army he answers "why would I think such a thing?". However, he then shows his brothers the newly created leg braces and crutches that were specially made in order for him to walk on his own.
Hvitserk and Ubbe go to see Ivar but Ivar's bodyguards initially stop them but they let them pass they find Ivar getting a tattoo of a giant snake. They question Ivar as to why does he need a bodyguard and Ivar explains the reason is that he is a cripple. Ivar shows his brothers that he can now stand and walk on his own feet with the help of new leg braces and a crutch. The Saxons led by King Aethelwulfand Bishop Heahmund entered the town through a section of the old Roman walls that were purposefully neglected by Ivar to lure the Saxons in the town. After the battle, the Saxons suffered a crushing defeat. Hvitserk and Ubbe propose a peace, but Ivar wants to continue the war. The two brother secretly leave at night to negotiate with the Saxons, Aethelwulf seemingly accepts their offer, but Heahmund arranges to have the brothers humiliated. With Ubbe having lost face, Ivar secures his position as the leader of the Great Army.
Hvitserk and Ubbe prepare to leave for Kattegat with their few followers however, at the last minute, Hvitserk defects to join Ivar. The Saxons lay siege to York, they massacred there hunting parties and blocked the city. the Vikings pretend to burn bodies, and Ivar humiliates Hvitserk by not sharing his plan. Hvitserk and Ivar are in the sewers of the city and Ivar informs Hvitserk that he has a plan. The city is deserted the Saxons celebrate but they are cut short when Vikings appear from the sewers and engage in battle. Bishop Heahmund is taken captive, Hivtserk and Ivar decide to take him with them to Kategat.
Taking the great army, Hvitserk, Ivar and the bishop traveled to Vestfold when they arrived they were greeted by Harald. Ivar made and alliance with Harald to attack Kattegat in exchange Ivar promised Harald that he would become his heir and they plan to attack Kattegat in two months' time. Hvitserk then questions Ivar why would he make Harald his heir and Ivar states who's to say he will Harald will not die. Ivar threatens and persuaded Heahmund to fight with them. After two months The army of Hvitserk, Ivar, Harald line up against the forces of Lagertha, Bjorn and Ubbe, meet above Kattegat. Lagertha sends Emissaries then negotiations take place Hvitserk was traded as a hostage for Halfdan. Ubbe pleads unsuccessfully to Hvitserk to side with him The leaders of the two armies met again the next day. Bjorn Ironsides begs Ivar to consider the possibility of peace stating that a civil war can only bring tragedy, and “a lifetime of revenge obligations for those who survive.” Here all diplomacy failed and the armies had to result in battle. Ivar agrees but tricks and mocks Lagertha and her alies. Before battle, Ivar takes Astrid and a third of their army towards shore, to protect their fleet. Hvitserk and his group try to flank, but are ambushed in the forest by the Sami. Battle begins, and Bjorn and Lagertha gain the upper hand, as Harald's forces are outflanked. Ivar hears the fighting, but says it is too late to help. Heahmund is wounded, and Harald retreats
Hvitserk is often seen alongside his brother Ubbe, and likely looks up to him. However, over time he grows to deeply dislike Ubbe, either recently for his failed plans and attitude or for his command of him over the years. Hviserk could also be manipulating Ivar into trusting him by pretending he also has a hatred of Ubbe. Later, he surprisingly suggests that Ubbe should be killed for not siding with them, leading more credence to the possibility of his manipulation.
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. It later becomes clear that Hvitserk is very sadistic and seems to be closer to Ivar than to Ubbe, leading him to choose Ivar over him.
Even if in is first raid he was save by both Bjorn and after Rollo,Hvitserk grow up and become one of the best Vikings warrior. Capable to match in single combat against King Aethelwulf and later slaying Guthrum in battle.
- 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).
- According to History, Hvitserk/Halfdan died in battle at the hands of fellow Vikings in Northern Ireland. He was king in Dublin but his rule was not secure there and while he was away in York, where he also was king, they deposed him. He sailed back to Ireland with an army in 877 to recapture dublin. But he was met with an army of what the sources call “Fair Heathens” and Hvitserk/Halfdan himself led an army of “Dark Heathens”. Both were rivaling groups of vikings in Britain and Ireland. There was a battle at a place called Strangford Lough in which Halfdan/Hvitserk was slain and his army also defeated.
- 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.
|Season two appearances|
|Brother's War||Invasion||Treachery||Eye For an Eye||Answers in Blood|
|Unforgiven||Blood Eagle||Boneless||The Choice||The Lord's Prayer|
|Season three appearances|
|Mercenary||The Wanderer||Warrior's Fate||Scarred||The Usurper|
|Born Again||Paris||To the Gates!||Breaking Point||The Dead|
|Season four appearances|
|A Good Treason||Kill the Queen||Mercy||Yol||Promised|
|What Might Have Been||The Profit and the Loss||Portage||Death All 'Round||The Last Ship|
|The Outsider||The Vision||Two Journeys||In the Uncertain Hour Before the Morning||All His Angels|
|Crossings||The Great Army||Revenge||On the Eve||The Reckoning|
|Season five appearances|
|The Departed Part 1||The Departed Part 2||Homeland||The Plan||The Prisoner|
|The Message||Full Moon||The Joke||A Simple Story||Moments of Vision|