Mr. Jergen was apparently involved in the shipping of Russian mail-order brides, as he describes an incident in which an associate fell in love with one. (Buridan's Ass) At another point, he helped pull an arrow out of his cousin when a man named Craig began laughing at him, so he threatened the man with a knife. (Who Shaves the Barber?)
Finding Sam's killer
Jergen is first seen at a Chinese restaurant among the rest of the mob where he tells his associates stories of previous jobs while ordering drinks. Moses Tripoli interrupts the conversation to ask about the status of the Sam Hess case. After Mr. Carlyle gives his boss the detailed numbers, Tripoli turns to Jergen for more information. Jergen tells him they don't think the murder of Hess was related to the business, though it could be extramarital on the wife's side. He has sent Numbers and Wrench to a second location to apprehend who they think is responsible. Tripoli corrects him, saying the perpetrator should be dead, not apprehended. Jergen agrees with him. (Buridan's Ass)
Jergen is later seen exiting the restaurant with Tripoli and the rest of his men who enter the building next door. On the way there, he continues stories of his violent history. Unbeknownst to him, Lorne Malvo follows shortly behind them and guns down everyone in the building. Jergen tries to stop him but is thrown out of a window and falls to his death. (Who Shaves the Barber?)
- Judging by his accent and his Dutch surname, which may indicate Boer heritage, it is most likely that Jergen is South African.