Thor Gundersen is known as “The Swede” despite his Norwegian heritage. Appointed head of security of Hell on Wheels by Thomas Durant, he was charged with maintaining a semblance of order in the chaotic and dangerous railroad town. A man of puritan simplicity and a survivor by nature — he survived the horrors of a Confederate POW camp, Andersonville, during the Civil War — The Swede is convinced that Cullen Bohannon is a murderer and becomes obsessed with bringing him to justice.

The Swede regularly extorts the residents of Hell on Wheels, and is ultimately tarred and feathered and run out of town by an angry mob led by the McGinnes brothers. Fallen from grace, he returns to take the undignified position of muckraker, collecting dead bodies and emptying latrines amongst the filth and refuse of Hell on Wheels.