With a departure point on the inequality between Swedish primary schools with regard to access to staffed school libraries as well as on the recent revision of the curriculum with regard to the principal’s responsibility, I have examined how responsibility for the school library is implemented in practice by conducting and analyzing qualitative interviews with five school librarians. The study draws on new institutional theory as well as professional theory in order to explore what school librarians value in terms of competence and education, as well as other factors that may affect the school library. Results show that the integration of school libraries into regular educational activities is largely dependent on the skills, interests and priorities of individuals. School librarians require greater recognition from principals and teachers as legitimate actors within the institution by being included in regulatory, governing documents. Legitimation requires principals to recognize the value of the school library and to allocate time for its work. The findings show that principals have jurisdiction over an area where they may lack professional knowledge. The informants emphasize professional training and pedagogical skills as integral to the legitimation process.