The Rennie Center for Education Research & Policy partnered with The Boston Foundation to examine and document the school-level practices that have enabled high growth and high academic achievement at the Pioneer Charter School of Science II, the winner of the 2021 Pozen Prize for Innovative Schools. The Rennie Center began with a review of existing literature, documenting practices that support high academic achievement in science, technology, engineering, and mathematics. Scholarly research supported the development of a research protocol, which guided site visits at Pioneer. Information presented in this case study reflects findings from a data review, school observations, interviews, and focus groups with students, community members, teachers, and administrators at Pioneer.