The use of Classical Greek myth as a narrative and metaphorical tool can contribute to the construction of a professional teaching identity. Adopting a biographical narrative approach, the present study sought to assess this contribution in a group of teacher and researcher trainees undertaking a postgraduate university course. The construction of personal narratives used for collective interpretation by the participants that generated them was analysed and interpreted in relation to the development of teacher professionalism. Our findings show the effective activation of metacognitive processes in order to rethink teacher professionalism from a narrative point of view. Using the structure and content of Classical myths as a scaffold, participants established valuable reflections on crucial aspects of teaching, identifying personal achievements and conquests as well as fears and insecurities. The structures latent in myth provided an effective framework with which to project and identify at least three hermeneutical themes—symbolism, function and structure—that form constituent elements of professional identity and are not only intertwined but are also constituted within a community of practice. Thus, Greek myths continue to offer an interesting cognitive and emotional scaffold that contributes to teacher professionalism, facilitating the formulation of a reflective, collaborative and personal meaning of identity which brings together personal teaching experiences and knowledge and is necessarily shared with the surrounding community of practice.