This article discusses the fruitfulness of Laurent Thévenot’s pragmatic sociology of engagements to the study of change in professional authority, a central yet unresolved theoretical issue in the sociology of professions. Invoking Andrew Abbott’s seminal notion of professional jurisdiction as starting point, the article uncovers how pragmatic sociology’s landmark model of dynamics of justification contains the seeds of an original reworking, build on plural grammars of legitimacy for shoring up public-political authority for expert-professional groups. Adding to this, Thévenot’s elaboration of plan-based and familiar engagement regimes allows one to grasp the equally important role of professionals’ co-shaping of state regulatory instruments and work practices of experience-based judgment, respectively. Professional authority, in this framework, is sustained and undergo meso-historical change at the intersection of these three engagement regimes. Illustrations are drawn from three collaborative case studies of inter-professional coordination in domains of urban climate adaptation, lifestyle disease prevention, and innovation management.