To what extent and in what ways should a teacher educator contribute to a type of teaching development that has long functioned successfully without much involvement of teacher educators? This self-study concerns my learning about my role as teacher educator in a learning study, a Hong Kong adaptation of a teacher-driven Japanese educational and cultural practice, Jugyou Kenkyu, credited with high quality learning outcomes for both teachers and students. My first learning study case forms the retrospective backdrop to the self-study. By describing and evaluating my personal experience of interactions such as recorded meetings and teachers' reflections, I attempt to discern a function for myself within the group. The self-study helped uncover some misguided assumptions and responses in coping with the new context and also provided some preliminary understandings of possible teacher educator responsibilities in this type of initiative.