She is known to international audiences for her roles as Astrid on the History Channel series Vikings and Pernilla Blomkvist in The Girl with the Dragon Tattoo (2011).

Asplund grew up in the suburbs of Stockholm, Sweden, with her Polish mother, Swedish father and older sister.

[4] Asplund began acting at the local theater close to her home at the age of 6, where she played various characters in different musicals until her teenage years.

During her childhood the stage was one of few places that truly felt like home, she said in an interview with Swedish Radio.

Shortly after, she was cast in David Fincher's adaptation of The Girl with the Dragon Tattoo opposite Daniel Craig.