A journalist, publisher of the political magazine Millennium, and the protagonist of the novel. Ethical, earnest, and a little naïve, Blomkvist accepts a freelance job to solve the mystery of Harriet Vanger’s disappearance in order to restore his good name after a libel conviction threatens his journalistic career and the future of his magazine.
The secondary protagonist of the novel and the titular girl with the dragon tattoo. Though iconoclastic and emotionally withdrawn, Salander is also fearless and a prodigiously skilled hacker, making her an ideal partner for Blumkvist in his investigation into the Vanger family.
A wealthy industrialist and head of the Vanger companies. He devotes most of his life to uncovering the cause of Harriet’s death and appears to hold his family, which he apparently despises, responsible for her fate.
The second of two serial killers in the novel, Henrik’s great-nephew, and one of the primary antagonists. Despite his position as acting head of the Vanger companies and a seemingly benevolent demeanor, Martin hides a sadistic streak: in the tradition of his father before him he seeks out women to kidnap, rape, and murder.
The editor-in-chief of Millennium and Blomkvist’s lover. Loud, brassy, and opinionated, Berger often expresses disagreement with Blomkvist’s decisions and his choice to work for Henrik but nonetheless offers what support she can.
A corrupt financier and one of the novel’s secondary antagonists. He considers himself to be above the law, and he manipulates the media to leak information, protect his reputation, and hide his criminal activities.
Henrik Vanger’s missing great-niece and the subject of Blomkvist’s search.
Salander’s second guardian. He is a brutal and sadistic man who sexually assaults Salander and uses her guardianship to control her.
One of Henrik’s cousins. She works as a headmistress and briefly becomes Blomkvist’s lover.
The managing editor of Millennium and a mole working on behalf of Hans-Erik Wennerström to leak information about the magazine.
The art director and designer of Millennium and the voice of reason in debates between Blomkvist and Berger.
Salander’s first guardian. In contrast to Bjurman, Palmgren exemplifies the best of the guardianship system, and he earns Salander’s respect and a small measure of her trust.
Martin’s and Harriet’s father and the first serial killer in Hedeby. Twisted beyond measure, Gottfried molested and abused both of his children and inducted Martin into the practice as well.
Cecilia’s sister and the woman responsible for Harriet’s flight from the island.
Blomkvist’s daughter by his ex-wife.
A hacker and one of Salander’s acquaintances.
The mother of Harriet and Martin and a source of frequent trouble for Blomkvist.
Cecilia’s brother and a verbally abusive older man who dislikes Blomkvist’s presence in Hedeby.
The CEO of Milton Security and Salander’s boss.
Henrik’s lawyer and confidante.