School-based initiatives can have a meaningful impact on K-12 teacher sustainability and retention. This study sought to investigate the state of teacher sustainability at one Boston charter school during the height of the COVID-19 pandemic. Participants and data collected in Cycle 1 consisted of semi-structured interviews with teachers, students, and non-teaching staff, all of whom provided input on the condition of the school following its return from remote learning. Action steps were designed, implemented, and evaluated in Cycle 2 to support leaders in reforming practices around teacher sustainability. Teachers convened in sustainability focus groups and drafted specific sustainability recommendations for school leaders. Action steps were implemented and a second round of interviews were held to evaluate the changes. The study concluded that in-school factors such as leadership continuity and teacher empowerment can significantly impact teacher sustainability and retention, but that more systemic factors such as compensation and cultural prestige continue to be influential. Implications for the organization included measuring the impact of the pandemic and mobilizing the community towards improved teacher retention. (PsycInfo Database Record (c) 2023 APA, all rights reserved)