The purpose of this study was to explore the multifaceted leadership role an effective principal assumed in the deployment of evidence-based literacy practices in her school. We conducted a mixed methods case study integrating the lived experiences of 11 school staff (principal, learning support teacher, and classroom teachers) with the reading scores of 122 Grade 1 to 3 students in Alberta (Canada). A merged mixed analysis strategy revealed four interdependent influences pointing to key contributions of the principal in igniting awareness, developing expertise, creating momentum, and leveraging data in relation to literacy school practices. Our findings shed light on the complexity inherent in the roles of principals and their interactions with others in developing evidence-based literacy school cultures that improve students' performance.