Large-scale police reforms in the Netherlands and Scotland were accompanied by transitions in police leadership. For the purpose of comparative research, unique interview data were collected among the Dutch and Scottish strategic police chiefs who were in charge prior to the completion of the reform process. It was found that police reform trajectories in the Netherlands and Scotland were both political projects aimed at generating more efficiency and cost-effectiveness through the centralization of police governance. Police leaders who were involved in the police reform trajectories expressed that their professional voice was largely neglected or immobilized through exclusionary practices. Moreover, it was found that deadlines prevailed over consensus and quality, impacting upon professional support for the restructuring process. The evidence-based insights help to identify critical success factors for large-scale organizational police reforms. A critical success factor is that police organizations adopt active learning and evaluation strategies before moving to a next transition.