In comparing the manner in which the careers of permanent CGT and CFDT personnel are constructed, this article examines the institutional work of codifying the professional mobility of union officials. It highlights the extent to which the mobility of these individuals is part of pre-established circuits, which are the subject of tensions and negotiations within militant structures. It also demonstrates the hybrid nature of the range of promotion on offer to union officials, founded on a combination of material and symbolic compensations. The article thus emphasises the importance to be attached to the often invisible symbolic dimensions of professional mobility.