The aim of this chapter is to discuss and reflect on changes in approach to leadership to encourage collaboration that are aligned with the principles of Complexity science for a holistic ecosystem of health and healthcare. It first discusses three theories of leadership: Ecological Leadership, Systems Leadership, and Distributed Leadership. It then analyzes the implications of these three theories for the three agencies of health and healthcare: Principles and Purposes (P1); People in Place (P2); and Practices and Processes (P3). The outcome is the assemblage of an ecology of lead(er) ship, termed the Dynamic Lead(er)ship Ecology of Adaptive Partnerships (LEAP) that is designed to encourage collaboration, adaptation and relationships. Finally, it reflects upon the link between the modes of cognition, methods of action to build relationships, and approach to  lead(er)ship, resulting in the assemblage of an ecology of cognition, action and lead(er)ship, termed the Action Cognition Ecology (ACE) of Lead(er)ship for health and healthcare.