This study examines the professional growth of a small group of in-service teachers undertaking a two-year part-time initial teacher education programme for primary English-as-a-second-language (ESL) teachers in Hong Kong. It aims to explore what meanings these course participants made of their professional education and how their prior experiences interacted with the teacher education programme in their construction of understanding in learning to teach English to young ESL learners. A case study methodology of the constructivist-interpretive research paradigm was adopted. The research findings suggest that professional development is a function of the teacher learner's pre-conceptions and resultant use of agency through construction of the professional self and knowledge about and of teaching. It is dispositional agency that guides teachers to grow in their cognitive functioning at a higher level. Through such a notion of agency, this study offers insights for a holistic understanding of teachers' professional growth. The book should be useful to teacher educators or professionals who seek input for more informed teacher education design or practice.