The development of Early Childhood Education in Sweden is a central concern for national and local government, and for school districts and preschools. While principals have the responsibility for, and a particular role in, leading education in the preschools, they are somewhat removed from the core work of teachers. In this article, we argue that it is ‘middle leaders’ who are the critical professionals for developing quality in education. The argument is made through examining the leading practices of middle leaders using a practice theory framework. We specifically draw on the theory of practice architectures to explore and understand the arrangements and conditions that enable and constrain the practices of these leaders in their work. The study draws on survey data and recorded professional Learning Dialogues among participants. Responses revealed a number of enabling and constraining conditions relating to particular cultural–discursive, material–economic and social–political conditions that influenced what was possible in their leading practices. Results further show how the practices of middle leaders were crucial in not only developing but sustaining quality in Early Childhood Education as they coordinate between the educational practices within the preschool and across the city district.