AbstractThis paper seeks to better understand how unanticipated disruption influences teacher agency and professionalism. Drawing on a conceptual model of teacher agency the paper examines data from teacher focus groups conducted in one Australian K-12 school to understand the lived experience of teachers (n = 50) during an initial COVID-19 lockdown period, particularly how they successfully navigated the transition to online teaching, and subsequent changes in practice and pedagogy. A grounded theory approach to data analysis revealed five conditions shaped teacher experience and a sense of personal achievement during this disruption: (1) an open individual mindset; (2) permission to be flexible and respond in appropriate ways; (3) reduced complexity; (4) effective relationships with leadership, colleagues, students, and parents; and (5) parental support. Temporal and affective dimensions of teacher agency (iterational—past; projective—future, and practical-evaluative—present) were used to explore the relationship between the five conditions and action for change. Findings suggest teacher agency was enhanced by focused school-based support which enabled teachers to deal with rapid change. Such support effectively facilitated reduction in complexity, provided structural and systemic assistance, valued and respected teachers as the professionals best placed to manage the shift to online learning, provided teachers with permission to try and fail, and enabled collegial support through a variety of communities of practice and structural support. Implications and future areas of research presented.