Background: Concussion public policies have been developed to address the burden of concussions. The aim of the present study was to examine implementation compliance, barriers, and facilitators of Canada's first concussion public policy, Ontario's Policy/Program Memorandum 158: School Board Policies on Concussion (PPM158). Methods: An electronic survey was sent to 515 randomly selected elementary and high school principals across specific geographic, language, and publicly funded school types in Ontario. Data were analyzed using both qualitative and quantitative methods. Results: One hundred and thirty-five principals responded to the survey (26%). Concussion education was provided to teachers in 81% of schools, to students in 83%, and coaches in 79%. Additionally, 89% reported having a return-to-learn protocol in place and 90% reported having a return-to-play protocol. Implementation barriers included difficulties in providing concussion education to parents (42%), obtaining notes from physicians, and maintaining the volume of documentation. Eighty-seven percent of respondents believed that PPM158 improves student well-being. Conclusions: Identified implementation barriers and facilitators can inform concussion policy practices to improve student well-being. We recommend: (1) an appointed concussion policy lead at each school, (2) electronic documentation, (3) determining the optimal education format to improve parent/guardian education, (4) fostering relationships between schools and health care professionals, and (5) student concussion education in every grade in Ontario schools.