The Covid-19 pandemic has provoked a turbulent and uncertain time, especially for young people. Globally, schools have responded to the evolving pandemic using the best available insights, data, and practices. This response has included a renewed focus on the importance of school mental health as a protective and stabilizing influence. In Ontario, strategic investments in school mental health, inclusive of foundational infrastructure, scalable evidence-informed interventions, and embedded implementation supports, allowed school boards to mobilize quickly during Covid-19, and to act within the context of an overarching multi-tiered strategy. In this article, we describe foundational elements that contributed to rapid mobilization and response in school mental health service provision in Ontario schools during Covid-19.