PURPOSE: The article aims to argue that the concept of "distributed leadership" lacks the specificity required to allow a full understanding of how change happens. The authors therefore utilise the "Strategic Action Field Framework" (SAF) (Moulton and Sandfort, 2017) as a more sensitive framework for understanding leadership in complex systems. The authors use the New Care Models (Vanguard) Programme as an exemplar. DESIGN/METHODOLOGY/APPROACH: Using the SAF framework, the authors explored factors affecting whether and how local Vanguard initiatives were implemented in response to national policy, using a qualitative case study approach. The authors apply this to data from the focus groups and interviews with a variety of respondents in six case study sites, covering different Vanguard types between October 2018 and July 2019. FINDINGS: While literature already acknowledges that leadership is not simply about individual leaders, but about leading together, this paper emphasises that a further interdependence exists between leaders and their organisational/system context. This requires actors to use their skills and knowledge within the fixed and changing attributes of their local context, to perform the roles (boundary spanning, interpretation and mobilisation) necessary to allow the practical implementation of complex change across a healthcare setting. ORIGINALITY/VALUE: The SAF framework was a useful framework within which to interrogate the data, but the authors found that the category of "social skills" required further elucidation. By recognising the importance of an intersection between position, personal characteristics/behaviours, fixed personal attributes and local context, the work is novel.