In this case study, we explore how principal candidates made sense of their internship by analyzing their weekly reflections during a school year. We found that candidates’ views of leadership developed from viewing leadership solely through the lens of making decisions and providing direction, to recognizing that much of the work of a school leader came from building relationships and delegating leadership responsibilities. Candidates’ experiences managing student discipline, conducting classroom walkthroughs and teacher evaluations, and leading professional development and professional learning communities (PLCs) were especially developmental. We conclude with implications for preservice training programs and future research.

High-quality principal internships are defined, in part, by support from high-quality principal mentors. We traced the development and quality of principal mentor–intern relationships during an academic school year and found that mentors played a significant role in determining the extent to which interns were isolated or integrated into the school leadership team. Specifically, mentors influenced (1) the types of tasks and activities interns were allowed to engage in, (2) the level of autonomy interns were afforded, and (3) the support interns received. Importantly, interns’ own proactivity shaped each of these aspects of their internship experience.