Background: Poor mental health outcomes persist among adolescent youth. Secondary schools play a critical role in fostering positive mental health by implementing policies and practices grounded in evidence. The factors associated with implementation, however, are unclear. This study examines which school- and state-level factors are associated with improved implementation of mental health policies and practices at secondary schools across the United States. Methods: US Centers for Disease Control and Prevention data stemming from 3 datasets (School Health Policies and Practices, School Health Profiles, and Youth Risk Behavior Surveillance System) surveys were integrated and analyzed. Results: Health educator certification, school use of data during school improvement planning, presence of a health/safety coordinator, presence of a health council and state-provided health educator professional development in mental health and suicide prevention were each significantly positively associated with schools' implementation of mental health policies and practices. Conclusions: To promote improved implementation of mental health policies and practices in schools and provide better support for youth mental health outcomes, the use of certified health educators and health-related supports should be considered. State health and education agencies should undertake evaluations of its mental health practices to ensure the assistance they offer to schools is evidence based.