["TESOL Quarterly, EarlyView. ", "\nAbstract\nThis study presents case studies of three early‐career secondary TESOL teachers in Japan, focusing on their professional development experiences. Their narratives were collected in two phases: (1) reflective reports submitted by the teachers during the fourth year of their teacher training, which included reflections on their previous L2 learning experiences, influential teachers, and insights from their practicum experiences and (2) a focus‐group discussion with a member of the research team with teaching experience, concentrating on the gap between the participants' expectations and the realities of the struggles and challenges they encountered early in their teaching careers, as well as their visions of their ideal future selves as educators. Data analysis revealed that (1) formative learning experiences in primary and secondary school strongly correlated with sustained commitment to teaching; (2) having experienced teachers as mentors with whom they could discuss both educational and personal concerns significantly impacted their professional development; and (3) university studies and study‐abroad experiences shaped their development as both learners and teachers. These findings underscore the importance of fostering supportive networks for early‐career teachers and facilitating opportunities for sharing and critical reflection in professional development.\n"]