A new model of care has been piloted in Ontario that expands the role of radiation therapists to improve access and treatment quality for patients requiring radiation therapy. The advanced practice Clinical Specialist Radiation Therapist (CSRT) role was created to redistribute activities amongst healthcare team members, allowing each to work to the full scope of practice, thereby better streamlining services, addressing systematic pressures in the existing model of care, and increasing patients' access to treatment. This paper provides an overview of the approaches used to develop and implement an advanced practice (AP) role, and it offers guidance on the use of an evidence-based approach to the evaluation of such positions. This article also utilizes the experience and knowledge developed during the CSRT projects to provide a framework for organizations embarking on similar AP implementation initiatives.