The impact of substance use disorders on the Canadian healthcare system is large, contributing to high use of hospital resources. At the Centre for Addiction and Mental Health (CAMH), Canada's largest mental health and addictions academic teaching hospital, substance use disorders constitute the primary diagnosis of 31% of annual inpatient admissions. Clinical nurse specialists (CNSs) with expertise in addictions are ideally prepared to promote competency development among baccalaureate-prepared nurses who are caring for this population. Despite recent advocacy to advance the addictions nursing workforce in Canada, recruitment of graduate-level CNSs in this field remains a challenge owing to a shortage of candidates with addictions expertise. Healthcare organizations specializing in substance use treatment must use innovative professional development strategies to foster nursing leadership that addresses the complex needs of this clinical population. In this paper, we describe the implementation of an innovative competency-based professional development framework designed to build capacity of CNSs at CAMH.