This thesis focuses on the study of the shaping process of the professional identity (PI) of preservice teachers (PT). Usual in institutional, professional and scientific contexts, the concept of PI is of a polysemous character, which gives it all its complexity and interest. The institutional discourse reflects an often reaffirmed concern about PI, but paradoxically, a virtual absence of explicit mention of it. From a scientific standpoint, the multiplicity of theoretical models that define the PI is at the origin of the semantic ambiguity characterizing it. By entering the culturalist theories (Engeström, 1999; Leontiev, 1975; Vygotsky, 1960), the postulates of clinical activity (Clot, 1999), of psychodynamics (Dejours, 1993) and of ergonomics (Wisner, 1995), this thesis provides a new perspective on the concept of PI, analyzing it as an activity to renormalize Prescriptions as recognized by oneself and by others. Conducted with six PT, the clinical approach allows the reconstruction of their individual routes and the identification of common characteristics in shaping their PI. Results highlight the identification of four turning points, corresponding to the steps common to all PT in the PI process. These turning points reflect the dynamic and unique shaping of the PI. They lead to the construction of scenarios shaping individual identity that break with the typical scenarios found in many studies. Proposals for rethinking initial training in terms of PI are outlined.
