Six months prior to filming, Noomi Rapace started training, learning all sorts of different boxing techniques. This wasn't because these skills would be showcased in the films but to make her body more masculine or androgynous in its appearance. (Although Lisbeth Salander is attracted to both men and women, she never appears truly comfortable in her own skin.) Rapace also worked with a dietitian to help make her as skinny as possible. She also had multiple piercings and learned how to ride a motorbike, earning her license just as filming commenced.
Dr. Anders Jonasson was originally named Anders Jakobsson, after a real-life doctor and close friend of Stieg Larsson. The real Jakobsson, however, confronted Larsson's father and brother about having denied Larsson's partner, Eva Gabrielsson, a share of the literary estate. In retaliation, the surviving Larssons changed the character's name.
The original novel also features a fictional appearance by a real person. In this case, former Prime Minister Thorbjörn Fälldin.
Veteran actor Per Oscarsson's last film. He died in a house fire the following year.
While Lennart Hjulström's character Fredrik Clinton tries to decide what to do with Mikael Blomkvist while lying on the sofa in his office, above his head lays a copy of Serbian newspaper called "Novosti" dated January 22nd 2008.
Released only two months after The Girl Who Played with Fire (2009), this holds the record for shortest gap between film sequels.
The container for the U.S. DVD release lists a running time of only "2 hr 9 min." The film on the disc is the full 148-minute (2hr 28min) version.