School librarian guidelines encourage active leadership in schools. Two ways school librarian educators can encourage school librarians to be leaders are to embed the standards into the certification curriculum and to assess the leadership potential of pre-service school librarians in order to adapt the curriculum to their needs. This mixed-method study examines how a pre-assessment of leadership potential was implemented in a school librarianship certification program that emphasized leadership skills. The results of the study indicate that the leadership pre-assessment implemented during the program application process effectively identified teacher leaders with the potential to be exceptional school librarians. This signifies that leadership pre-assessments can enable school librarian educators to help pre-service school librarians to improve their leadership skills.