Leadership mentoring and situated learning are important components in the effective preparation of candidates for school principalships. This study examined this assertion through responses to reflective writing prompts and to interview questions by students enrolled in three different closed cohorts in the same university-based preparation program. Readiness to assume a principalship appears to be linked to an individual's (a) encouragement and support from leadership mentors; (b) opportunities to engage in authentic leadership activities; and (c) perceptions of personal competence to assume school-leadership responsibilities. To develop these elements, especially as pools of principals shrink, preparers should carefully select leadership mentors for aspiring administrators and organize authentic problems of practice in schools, which expand opportunities for aspirants to apply knowledge in practice. In this vein, three models of leadership mentoring during full-time authentic school-leadership practice are described. (Contains 4 tables.)