Context: In Adult Mental Health Inpatient Units, it is not unexpected that leadership of Associate Nurse Unit Managers contributes to successful implementation of smoke-free policies. Aim: In light of challenges facing mental health nursing, and limited research describing their leadership and the role it plays in addressing smoke-free policy implementation, the aim of this study is to explore Associate Nurse Unit Managers perspectives' regarding the implementation of smoke-free policies, which were introduced on 1 July, 2015. Design, Setting, Participants: Individual in-depth semi-structured interviews were undertaken six months post the implementation of smoke-free policies. In this qualitative descriptive study, six Associate Nurse Unit Managers working in a Victorian public Adult Mental Health Inpatient Unit, were asked eight questions which targeted leadership and the implementation and enforcement of smoke-free policies. Associate Nurse Unit Managers provide leadership and role modeling for staff and they are responsible for setting the standards that govern the behavior of nurses within their team. All participants interviewed believed that they were leaders in the workplace. Main Outcomes: Education and consistency were identified as crucial for smoke-free policies to be successful. Participants acknowledged that the availability of therapeutic interventions, staff resources and the accessibility of nicotine replacement therapy were crucial to assist consumers to remain smoke-free while on the unit. Conclusion: The findings from this research may help to improve the understanding of the practical challenges that Associate Nurse Unit Manager's face in the implementation of smoke-free policies with implications for policies, nursing practice, education and research.