[7] Fangen began her career in 1993 as an assistant professor managing the youth sociology program at Sogn og Fjordane University College in Norway.
Her doctoral work explored the Norwegian rightwing extremist underground movement in 1990s Norway, analyzed by her fieldwork and cultural and modernization theories.
This underground movement consisted of three fronts—paramilitary groups, National Socialist skinheads, and ideological fronts—that, despite varying lifestyles and beliefs, united to combat militant anti-fascists.
[14] Moreover, her study looked into how the right-wing skinhead subculture, known for its militant appearance and Nazi gestures, differed from WWII Nazism by incorporating elements of rebellion and opposition to authority while still directing aggression towards specific ethnic and political groups.
[21] In 2022, a new edition of Fangen's first book, En bok om nynazister, originally published as her PhD thesis in 2000, explored the evolution of the neo-Nazi milieu in Norway, its shift towards Islamophobia, and the continued relevance of understanding right-wing extremism in polarized and internet-driven landscape.
[22] Fangen's book, Deltagende observasjon, published in 2004, provided an introduction to participant observation, covering fieldwork challenges, theoretical perspectives, and the processes of analysis and publication.
Kirsten Lauritsen remarked, "Katrine Fangen has written an important book for anyone who wants to understand more about the interaction between so-called "ethnic Norwegians" and Somalis in Norway than what the media typically provides.
It covers an important and wide spectrum of national experiences and policies of social inclusion and exclusion processes that migrant youth face in Europe.