Based on a study conducted in a juvenile detention centre in the French-speaking part of Switzerland, this paper examines how recent transformations in professional intervention have influenced changes in the meaning of confinement. We first analyse the rivalries of professional groups and the tensions between the established, childcare workers and vocational supervisors, and the outsiders, detention officers and medical staff. We then argue that the new moral economy of confinement is more related to an increase in interdependencies and rivalry between the different professional groups than to changes in the ‘meaning' of the criminal law. This evolution parallels a new legitimisation of confinement based on professional knowledge.