Action research is a methodology that has been increasing in educational studies in recent years. Previous studies have revealed that action research affects practitioners more than traditional methods, since the practitioners are not only participants but also researchers themselves. One branch of action research is collaborative action research (CAR), whereby practitioners and the researcher collaborate through the action research process. This study builds on material from CAR in one Icelandic preschool that lasted over 24 months. The focus of this article is on the role of the researcher in the action research project and how it was constructed through the process. The research material consists of the researcher's self-narratives, practitioners' diaries, interviews, and recordings from meetings. The findings show that the researcher's role was constructed in a so-called third space where the researcher and practitioners collaborated. The researcher went through an emotional landscape while constructing her role and her position was something in between an insider and an outsider. Finally, she faced different kinds of tension concerning her role as a researcher in the CAR. The study contributes to the limited number of studies on the researcher's role in CAR and how it is constructed during the process.