Despite ongoing efforts to recruit and support successful school leaders, relatively little is understood about the professional experiences and skillsets that principals possess upon entry into their positions. We trace the professional experiences and instructional effectiveness of all educators in Oregon over 14 years. We highlight that many principals acquire leadership experience outside the assistant principal role and outside of the school district in which they serve as principals. When future school leaders were teachers, they improved student achievement at modestly higher rates than their peers. Insight into these topics may inform the recruitment and professional development of school leaders.