Primarily driven by conflict, displacement and economic pull factors over the past three decades, a homegrown system of mother-tongue-based education for migrant children from Myanmar has been developed in Tak Province, Thailand. This network of Migrant Learning Centers depended mainly on external organisations for teacher professional development (TPD), with few Centres having opportunities to develop school-based models. This paper documents learning from creating the 'teacher leader' role to build school-level capacity to sustain TPD by giving new responsibilities to 31 teachers as peer coaches during the pandemic. Mixed-methods analysis used Hofstede's Cultural Dimensions Theory, specifically, Power Distance, Individualism -- Collectivism, Uncertainty Avoidance and Long-Term Orientation to frame sensemaking and the extent to which teachers' perceptions of the new role were consistent with its implementation. The teacher leader role contributed to a perceived reduction of power distance between teachers and promoted long-term orientation regarding TPD. Its emphasis on collaboration allowed collectivist ideals to be played out practically without disturbing the status quo. The prioritisation of reflective practice and teacher-level collaboration improved coaching self-confidence and teaching competencies. Teacher-led peer-support systems within and across schools assisted in the retention of institutional knowledge.