Many have suggested that charter schools can be key agents in leading dramatic improvements in public education. However, the small number of highly-successful charter schools and charter management organizations currently in operation throughout the country will have to grow much faster in order to meet this challenge. To achieve that growth, they also will need a strong supply of great teachers and leaders. This report, for the Center for American Progress, by Christi Chadwick and Julie Kowal, looks at six leading charter management organizations (CMOs) – Green Dot, High Tech High, IDEA, KIPP, Rocketship, and YES Prep – and the strategies they have implemented to build the supply of high quality teachers and principals in their schools. The paper also presents barriers and challenges that still remain for these CMOs, as well as promising opportunities to support more rapid future growth.