Schools are turning to research-based social emotional learning (SEL) practices to improve student achievement and school progress. Research to support SEL implementation, however, has lagged behind outcomes-based evaluations, often resulting in poor SEL program quality and fidelity. This mixed methods study explores SEL implementation at a high-needs high school to determine the extent the program's implementation adhered to the identified model. The findings indicate the study school only minimally implemented the evidence-based model due to barriers also cited in peer-reviewed research and, therefore, the evidence-based program was not implemented as intended. This study validates the need for research to shift attention from efficacious outcomes-based studies toward establishing best implementation practices to ensure interventions are transferred and implemented with fidelity. Doing so should strengthen adherence to evidence-based models, improve the overall quality of SEL program implementation, and increase the likelihood of achieving the desired outcomes attributed to SEL program implementation.