The purpose of this chapter is to show the importance of intersectorality in partnerships to successfully understand and influence the processes of crime desistance and of social and community (re)integration of people subject to judicial control. It begins with an outline of the “what works” and “how it works” movements and provides tools to help understand such notions as crime desistance, (re)integration, trajectories, and intersectorality. After describing the objectives of the (RÉ)SO 16-35 partnered research project, the authors present various intersectoral collaborative initiatives in the United Kingdom, the United States, and Canada and indicate what, according to the literature, contributed to their development. The chapter concludes with the identification of two central principles in the development of intersectoral partnerships aiming to favor crime desistance and social and community (re)integration trajectories: a culture of dialogue must be instilled, and the initial objective of the project must be kept in mind.