| Adopting poststructuralist and sociocultural notions of identity, this thesis focused on the professional teacher identity development of two non-native speaker (NNS) preservice English as a foreign language (EFL) teachers in a one-year full-time Postgraduate Diploma in (Secondary) Education (PGDE) program in Hong Kong.;Following a mixed-method, longitudinal, multiple case study design, data were collected throughout their one-year teacher training program from September 2010 to July 2011. Five strategic data collection phases were designed with reference to the curriculum of their PGDE program -- (1) entry/pre-immersion, (2) post-immersion, (3) pre-practicum, (4) mid-practicum, and (5) post-practicum. The data included in-depth, semi-structured, individual interviews, documents (e.g. reflective writings, concept maps, teaching portfolios, field notes), and survey questionnaires. Qualitative and quantitative were triangulated and analyzed with a focus on the factors impacting the participants' professional teacher identity development.;The findings of the present study illustrated the rich and complex nature of professional teacher identity construction. Nine major factors that shaped the participants' professional teacher identity were identified: (1) prior beliefs and experiences (e.g., L2 learning), (2) motivation and attitudes (e.g., L2 motivation and attitudes, motivation to become a teacher), (3) dispositions and emotions, (4) goal orientation and coping strategies, (5) self-confidence (e.g., L2 confidence) and teacher efficacy, (6) reflective practices, (7) learning experiences in the PGDE program (e.g., PGDE courses, immersion, teaching practicum), (8) school and classroom environment in the TP, and (9) perceived expectations from school, parents, students, and society (regarding L2 proficiency, subject knowledge, accent, etc.).;Despite some similarities in their education background and learning opportunities in the PGDE program; the two participants, Lisa and Ella, followed very different paths in their professional teacher identity development. Their stories underscore the role of emotions, and the potentially beneficial or detrimental influences of the aforementioned factors on student teachers' professional identity construction.;There have been calls in the field for more qualitative studies on the professional identity development of student teachers and the challenges they face (Marais, 2013; Izadinia, 2013). This study enriches our understanding in these areas by comparing and contrasting the divergent developmental trajectories of the participants. Lisa successfully developed her professional teacher identity upon the completion of the program, while Ella rejected her identity as a qualified EFL teacher.;Practical suggestions are offered for teacher training programs, teacher educators, supervising teachers in the teaching practicum, local schools, and experienced teachers to help preservice or novice teachers construct their professional identity. |