In this chapter, we summarise the book’s contributions to knowledge in educational leadership, emphasising three crucial roles of theory. First, it enables insights into leaders’ identities, where questions of ethical or axiological “fit” into a performative policy landscape are addressed. Second, theory illuminates these structures within which leaders practise; and third, it prompts explanations concerning leaders’ agency regarding, for instance, a re-conceptualised professional judgement or moral purpose. Finally, we show how the book’s findings speak to four key aims of theory-informed critical scholarship: foregrounding theory; re-conceptualising educational leadership; problematising “leader” identities and revealing power relations and their inequitable effects.