Youth throughout the United States face physical and mental health concerns that threaten their wellbeing and academic success. This is especially true among low-income communities and communities of color. School-Based Health Centers (SBHCs) and Comprehensive School Mental Health Systems (CSMHSs) are evidence-based delivery models that provide essential health services to students and their communities, recognized for targeting barriers like transportation, cost, and time. This paper describes a national initiative to increase the number of SBHCs and CSMHSs, improve the quality of care delivered, and strengthen the sustainability of school-based health and mental health through Collaborative Improvement and Innovation Networks (CoIINs). In spring 2020, when schools nationwide closed abruptly due to the COVID-19 pandemic, this initiative provided participants an essential professional network and space to share challenges, innovations, and best practices to sustain high quality care delivered to students. Participants shared that their involvement encouraged staff and state agencies to work more closely together and provided protected time to focus solely on student health. The CoIIN was especially helpful as sites transitioned from in-person to telehealth care due to school closures. Participation helped sites engage in peer-to-peer sharing, comparison, benchmarking, and a continuous piloting of new strategies. This case report describes the CoIIN with a particular focus on implementation during COVID-19. This will benefit school-based health and mental health practitioners and stakeholders interested in employing a similar model of quality improvement and support.