Teaching perspectives in initial teacher education are useful analytical tools for exploring the development of professional identity and the supervisory practices of cooperating teachers working with preservice teachers on school placement. A case study design was employed with an experienced physical education teacher newly appointed as a cooperating teacher to a cohort of three physical education preservice teachers to examine how his professional identity was challenged by the demands of the new role as a mentor. Data were collected throughout a one-year school placement and included three semi-structured interviews and the cooperating teacher's weekly journal entries. Analysis was informed by grounded theory coding procedures. Open codes were collapsed into three metaphorical axial themes: (a) the chameleon, (b) a tailor-made cooperating teacher, and (c) the liaison of relations. To perform his new role as a cooperating teacher and surpass the emergent supervisory challenges in developing a pedagogical relationship with his first cohort of preservice teachers, the cooperating teacher called upon his educational perspectives on teaching physical education built on constructive, collaborative and inquiry premises, but ended up practising teaching perspectives echoing an apprenticeship model due to the preservice teachers' personal characteristics.