Abstract Purpose In this chapter, I reflect on the foundations of the “fair policing from the inside out” approach to identify elements that may complement and refine this theoretical framework. Methodology/approach I address the question of how fair policing can be achieved from a multidisciplinary perspective. Insights and empirical evidence from criminology, psychology, management, and political science/public administration are used to theorize the relationship between internal and external procedural justice. Findings Both the theoretical framework itself and the conceptual model that has been derived from it are refined. In total, four aspects are elaborated: (1) I stress more explicitly the potential mediating role of moral alignment with citizens; (2) I point more explicitly at the potential mediating role of trust in supervisors and moral alignment with supervisors; (3) I hypothesize that strain/stress may mediate the relationship between internal and external procedural fairness; and (4) I hypothesize several links between mediators. Originality/value This chapter contributes to the challenge of theorizing the origins of fair policing. It aims at widening the scope of police research.