Since the outbreak of COVID-19, language teachers have been asked to rapidly react and adapt to constantly changing teaching environments in order to understand their students’ needs in L2 learning and make judgments in conditions of uncertainty. The COVID-19 outbreak has highlighted the need to understand how teachers’ identities evolve during such difficult times and situations. In response to this need, this study reports the findings from my qualitative case study on a Korean English teacher’s identity shift. Drawing upon Foucault’s (1983) notion of ethical self-formation, I examined how the Korean English teacher negotiated and developed her identity to adjust to drastically changing working environments as she weighted the benefits and challenges of online and offline education, particularly for novice Korean EFL learners. Data were collected through various sources from an experienced Korean English teacher, called Anna, at a regional foreign language center in South Korea over the course of two years. Due to the pandemic, she had to make the transition from offline to online teaching. Further, her center closed one year after the outbreak of the pandemic, and she was reassigned as a travelling teacher in a multi-school program for underachieving English students. The findings reveal that Anna became more agentive in searching for and utilizing multiple resources for teaching, showing her reflective and action-oriented practices to involve in ethical, practiced, and productive identity work (Miller, Morgan, & Medina, 2017). The findings contribute to expanding our understanding of the transformative potentials of language teachers’ identity.