This investigation is a case study of a process of negotiation of professional identity of a Thai pre-service teacher during her teaching practicum through the lens of Symbolic Interactionist theory. It posits that interaction with different objects allows for complexity of professional identity formation to emerge. The participant's narratives in the form of reflections over 15 weeks were collected and transcribed for analysis. Key phrases of the participant's role claims were investigated to identify themes vital to observe her self-image as a teacher. Findings also revealed that the interaction with social objects i.e. her students as human agency, was found to be most influential on her identity formation. This study hopes to shed light on teacher training education on the importance of teacher identity, which is central to beliefs, assumptions and values that guide a teacher's practice in the process of becoming one.