Music teachers are pivotal to the future of music education and the value of the arts in society. Centrally important is the professional identity of music teachers, expressed through enacted pedagogical and curricular content. This inquiry investigated professional identity development in ten early career music teachers through an exploration of their beliefs, knowledges and experiences in and about music and music education. Using an a/r/tographic conceptual approach informed by Deleuzoguattarian rhizomic philosophies, the participants' individual journeys of 'becoming music teacher' were storied and re-storied, curated into seven research plateaus. As researcher, the work evolved to be partially autobiographical. The thesis is presented as opera (opus, plural), mapped to guide the reader through the work. Musical and gardening metaphors are pervasive throughout the work. Arts works, both visual and musical, are embedded, not 'as' research, but to explain the research. What emerged was multifaceted. Unanimously, the participants felt their identity as a musician was important to their sense of self and that being a practising musician/composer was central to becoming an authentic music educator. Early epistemic beliefs are central to teacher practices and in-school experiences either reinforced or challenged the development of professional identity and impacted longevity in the profession.