In this paper a sophisticated conception of individuality is developed that extends beyond simple heterogeneity and is consistent with the approach of institutional economics. Studies of human biological and psychological development are used to illustrate the foundations of human individuality and the impact of the social environment on individual development. The link between the social environment and ongoing agential properties is established through the role of habits, which provide some continuity to individual personalities over time and assist them in navigating the social context they inhabit. Reflexivity is established via an agency-structure framework that endows individuals a changeable self-concept and an ability to interpret their relationship to the social context. The coordination of different individuals is explained not simply through reference to institutional structure, but also through the agent-level properties of shared habits. While reducing differences between individuals to one of degrees, shared habits are shown to be particularly important in the context of agent-sensitive institutions. Finally, the potential for different institutional experiences to impact the reflexivity of individuals is explored.