Lisbeth is a 24-year-old freelance investigator working for Milton Security. She is a highly skilled computer hacker who operates by her own strict moral code, often disregarding conventional laws. Due to a traumatic childhood and institutionalization, the state classifies her as legally incompetent, requiring her to live under the supervision of a court-appointed guardian.

Mikael is a 42-year-old financial journalist and publisher for the political magazine Millennium. He built his career exposing corporate corruption but currently faces a brief prison sentence and professional humiliation following a disastrous libel case. Searching for an opportunity to restore his credibility, he accepts an unusual freelance assignment on remote Hedeby Island.

Henrik is an 82-year-old retired industrialist and the patriarch of the Vanger family. He lives on Hedeby Island and remains consumed by the 1966 disappearance of his beloved grandniece. Hoping for closure before he dies, he offers Blomkvist a lucrative contract to solve the decades-old cold case.

Erika is the editor-in-chief and part-owner of Millennium magazine. She manages the publication's daily operations and strategic direction during Blomkvist's leave of absence. She maintains an open marriage with her husband while carrying on a long-standing romantic affair with Blomkvist.

Martin is the current CEO of Vanger Corporation and Harriet's older brother. He lives in a sleek, modern house on the island that heavily contrasts with the older stone properties of his relatives. He maintains a friendly, sophisticated demeanor while managing the intense pressures of leading the struggling family business.

Harriet is Henrik's grandniece who vanished without a trace during a town parade in September 1966. At the time of her disappearance, she was a teenager showing an increasing interest in religion. Her fate remains the central mystery haunting the Vanger family.

Bjurman is a lawyer appointed by the state to manage Salander's finances and personal affairs after her previous guardian suffers a stroke. He uses his legal authority to exert cruel, systematic control over her life, demanding degrading concessions in exchange for access to her own money.

Wennerström is a powerful CEO and financier who operates a massive international investment empire. His successful lawsuit against Blomkvist damages Millennium's reputation and forces the journalist to temporarily step away from his profession.

Cecilia is Harald Vanger's daughter and a charismatic school principal. She lives on Hedeby Island but maintains a deep estrangement from her father and brother. She forms a brief, intense romantic attachment to Blomkvist during his stay in the guest house.

Frode is Henrik Vanger's trusted lawyer and close confidant. He handles the legal and financial arrangements for Blomkvist's contract and acts as a steady intermediary between the journalist, the Vanger family, and Milton Security.

Armansky is the CEO of Milton Security. Though initially skeptical of Salander due to her unconventional appearance, he comes to recognize her as his top investigator, granting her the freedom to take cases on her own terms.

Palmgren is an advocate for troubled youths and Salander's former legal guardian. He treats her with warmth and respect, offering her independence until a severe stroke forces him to relinquish his guardianship.

Gottfried is the deceased father of Martin and Harriet. During his life, he struggled with severe alcohol addiction and lived in a remote cabin on the island before drowning in a supposed accident.

Isabella is the mother of Martin and Harriet. She resides on Hedeby Island and remains cold and uncooperative regarding Blomkvist's presence and investigation.

Harald is a 92-year-old former Nazi sympathizer and Henrik's brother. He rarely leaves his home and harbors deep-seated animosity toward Henrik and his own daughter, Cecilia.

Anita is Cecilia's sister and Harriet's aunt, currently living as an airline manager in London. During their youth, she was Harriet's closest companion and confidante.

Pernilla is Blomkvist's 17-year-old daughter from his previous marriage. She maintains a loving relationship with her father despite his controversies and shows a growing, earnest interest in her religious faith.

Morell is the retired police officer who originally investigated Harriet's disappearance in 1966. He meticulously documented the case and shares his files and lingering frustrations with Blomkvist.

Malm is the art director and a part-owner of Millennium magazine. He works closely with Berger to keep the publication afloat during the fallout from the Wennerström trial.

Annika is Blomkvist's sister and an attorney specializing in women's rights. She provides her brother with a supportive family environment away from his professional crises.

Plague is an underground computer hacker and associate of Salander. He supplies her with specialized electronic equipment for her covert surveillance operations.

Mimmi is Salander's friend and casual romantic partner, offering her moments of connection outside of her isolated professional life.