An adult ego development (AED) perspective accepts that the way adults interpret and interact in the social world can change during their life-span. This article seeks to analyse the validity and potential of AED for enhancing understandings of educational leadership practice and development. We analysed the AED literature and interviewed 16 individuals in senior leadership positions in the English school system. The interviews enabled them to explore the notion of AED and to reflect on their own sense-making capability and their experience of school leaders they considered to be in the different stages of AED. Educational leaders judged to be in the different AED stages were encountered by respondents to varying extents and were experienced and valued differently. Those considered to be in the later AED stages appeared to be more highly valued and their sense-making capabilities may have substantial value in the complex working environment of schools. The analyses showed that: AED has a considerable role in educational leadership practice; can inform the analysis of educational leadership practice and development; and has valuable explanatory power.