Leadership is a core component of medical professionalism. The leadership provides a role which allows the clinician to take an overview of the service, thereby planning service delivery and service development. Professional bodies working together can help to define the distinction between professionalism and the leadership of teams, services or policy-making. This chapter examines the concepts of leadership within contemporary practice and policy contexts. It focuses on the range of ways that mental health professionals can lead and participate in promoting mental health with the engagement of clinical team members, professional organizations, employers and policy-makers. The chapter deals with leadership in the context of partnership-based collaborative care. Appropriate leadership is critical to supporting professionalism within current practice settings of increasing networking and joint working. Professionalism needs to be reconciled with distributed leadership and the many roles of mental health professionals.