Despite recognizing the importance of critical incidents (CIs) in teachers' professionalism, there is a need for more research on novice teachers' CIs, especially emotional CIs. This study describes the emotional CIs of a novice language teacher during her first year of teaching by relying on Schutz et al.'s (in: Schutz, Hong, Francis (eds) Research on teacher identity: Mapping challenges and innovations, Springer, 2018) conceptual framework and Zembylas' (Journal of Research in Science Teaching 39:79-103, 2002) three-dimensional framework of intrapersonal, interpersonal, and intergroup levels of teacher emotions. Data were collected from semi-structured interviews, observational field notes, stimulated recall interviews, and online narratives. The teacher's intrapersonal emotional CIs dominantly influenced her current functioning to eschew creating similar negative experiences for her students. The interpersonal emotional CIs created tensions that largely influenced her claimed identity as a professional teacher. The intergroup emotional CIs made her develop negative perceptions about certain ethnic groups and educational stakeholders. Moreover, the findings indicate that while the teacher could function agentively at the classroom level, her limited agency at the institutional level created tensions in her identity as a professional teacher. The study portrays how novices negotiate and construct their professional identity based on emotional CIs, shows how such CIs accelerate novice teacher attrition, and provides implications for reducing the emotional gap between policymakers and novice teachers.