This paper summarizes research on the Every Student Succeeds Act (ESSA) Leadership Learning Community (ELLC) and the University Principal Preparation Program (UPPI). The Wallace Foundation created these efforts and supported them financially to test ideas for improving the work of principals and enhancing the supports they receive on the job. While the ELLC and UPPI embraced that same overall goal, each operated with different constellations of actors, organizing frames, and concrete purposes. The analysis in this paper discerns key implications of each effort and also broader lessons for policymakers and their partners interested in developing and supporting excellent principals who advance teaching and learning.