Principals shape the academic setting of schools. Yet, there is limited evidence on whether principal professional development improves schooling outcomes. In 2008-09, Pennsylvania’s Inspired Leadership (PIL) induction program required that newly hired principals complete targeted in-service professional development within five years of employment. Using panel data on all Pennsylvania students, teachers and principals, we leverage within-principal variation in the timing of PIL completion within the same school setting to estimate the impact of PIL induction on principal persistence, teacher effectiveness and student achievement. PIL induction increased principal tenure by 18 percent, corresponding to approximately half an additional year as principal of record; however, PIL induction had no impact on teacher effectiveness or student achievement. We discuss the implications of our findings for principal induction efforts.