This chapter presents a particular approach to ‘sociological institutionalism’ which I have developed through research and reflection on planning and urban regeneration ideas and practices. This emphasises a dynamic, relational view of institutional formation, stabilisation and destabilisation and centres on understanding institutionalised practices ‘in action’. The chapter is in two main parts. The first provides an account of how I built up the approach and the second outlines its main dimensions. I conclude by addressing, though this approach, three questions: How should we think about the structuring role of institutions? How should we think about institutional transformation and change? And what is the implication of a ‘pragmatist philosophy’ for evaluating and designing institutional innovations?