After finishing school and his military service, Stieg Larsson worked a couple of years at a post office. During these years in the mid-seventies, he was an active member of the Swedish left-wing movement which flourished during these years. He edited a Trotskyite magazine, and he took a great interest in the ongoing war in Vietnam.
1977, Stieg Larsson started working as a graphic designer at TT, a multimedia news provider in Sweden, a job he kept for the following 22 years. As the seventies passed, Stieg Larsson's interest gradually turned more towards right-wing extremism, an interest which had started with a school project on the subject and then continued to inspire him for the rest of his life. When he was not at his work at TT, he worked on a private mapping of right-wing extremism in Sweden. In 1991, his research resulted in his first book "Right-wing extremism" ("Extremhögern") which he wrote in cooperation with Anna-Lena Lodenius, a Swedish writer specialized in autonomous and national extremist groups. In an interview she says that he had plans on writing a series of detective novels already back in the early 1990's, but it would take another ten years for him to start writing fiction.
As a response to the book "Right-wing extremism", a neo-Nazi newspaper published an article in 1993. In the article, both Larsson and Lodenius were presented with their pictures, addresses and telephone numbers, and the finishing lines raised the question whether "he should be allowed to continue his work, or if something should be done". The publisher of the newspaper was condemned to 4 months of imprisonment. However, this episode did not scare Stieg Larsson, instead it convinced him to step up his struggle. Stieg Larsson had since the early 80's worked as a Scandinavian correspondent for the British anti-fascist magazine Searchlight, and in 1995 he was the main force behind the founding of the similar Swedish magazine Expo in 1995. For two years, he combined the two full time jobs before he finally quit TT in 1997 to put all his effort into Expo. From 1999 to his death, he was the chief editor of the magazine.
When you look at the combination of working at Expo with writing books on right-wing extremism, holding lectures for international politicians, police forces and numberless youths, writing his detective novels at night, smoking 60 or more hand-rolled cigarettes a day and skipping most meals, the picture of a classic workaholic appears. In an article in the Swedish newspaper Expressen, the journalist, co-worker and close friend of Stieg's, Kurdo Baksi verifies this, "He used to come home at four-five in the morning. At that time had he also worked on his story about Mikael Blomkvist and Lisbeth Salander. "It will be better next year", he (Stieg) said brightly.