The answer to the question is Nordström. Joel Kinnaman's original surname is Nordström, which is a common Swedish surname meaning "northman" or "northerner". It is one of the most popular surnames in Sweden and is shared by many prominent Swedes, including the actor Stellan Skarsgård and the singer-songwriter Robyn.
The Joel Kinnaman Trivia Challenge: How Well Do You Know This Swedish-American Actor?