This dissertation, "From Prospective Teachers to First-year Teachers: Antecedents and Malleability of Teacher Identity" by Bing, Li, 李兵, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Teacher identity is at the heart of the teaching profession. However, the literature is replete with studies reporting "tensions," "personal struggle," or "traumatic experience" relating to teacher identity, particularly among the early career teachers. The prime objective of the present research was to explore possible reasons behind the aforesaid phenomena by: 1) tracking the change in teacher identity through following fresh graduates from a teacher training program till the end of their first year of teaching; and 2) examining the roles of two groups of antecedents, that is, contextual factors (perceived learning/work environments) and intellectual styles (thinking/teaching styles), in shaping and reshaping teacher identity during this transition. The present research also looked into the mediating functions of intellectual styles in the relationships of learning/work environments to teacher identity. Moreover, the association between thinking styles and teaching styles was investigated. In the present research, teacher identity was manifested through four indicators: teacher self-efficacy, organizational commitment, motivation to teach, and job satisfaction. Learning environments were assessed from a constructivist perspective. The Job Demands-Resources model provided a lens through which work environments were conceptualized. Intellectual styles were operationalized drawing on the threefold model. The present research employed a quantitatively-driven mixed approach and comprised three studies: a pilot study, a main study, and a follow-up study. The pilot study validated five inventories and preliminarily examined the hypothesized relationships. The main study was a two-wave quantitative one. In this study, 1,062 Year 4 prospective teachers from a teacher training program in mainland China responded to three inventories (measuring learning environments, thinking styles, and teacher identity); and, one year later, 464 of them responded to three inventories (measuring work environments, teaching styles, and teacher identity) after finishing their first year of teaching. Finally, 18 participants who had shown the greatest change in teacher identity over one year were selected to participate in individual semi-structured interviews in the follow-up study. Results of the main study lent substantive support to all the four research hypotheses. First, learning/work environments and thinking/teaching styles were at least partially held accountable for the shaping of the participants' teacher identity. Second, teacher identity was malleable. In general, the participants' teacher identity declined significantly. Among others, job satisfaction showed the most considerable magnitude of decrease, followed by leadership self-efficacy. This decline could be at least partially attributable to the excessive job demands (particularly emotional demands) and the lack of job resources (particularly growth opportunities and superior support) in these participants' perceived work environments. Third, the impact of learning/work environments on the participants' teacher identity might not be direct, but rather mediated by intellectual styles (particularly Type I styles). Fourth, the participants' thinking styles and teaching styles were moderately consistent over one year. Findings of the present research theoretically contribute to the literature on the five key var