This study investigates two distinct ways of organising heritage language education within one national context. More specifically, we investigate the teaching of Greek in Sweden through: (a) mother tongue instruction provided by the national education system and (b) a complementary school run by a parental organisation. Drawing on Archer's morphogenetic approach (1995), where structure, culture and agency are seen as separate but interrelated analytical layers, we investigate key actors' agentive responses to structural and cultural enablements and constraints. The study includes a historical overview and a linguistic ethnography conducted in both contexts. The data encompass policy documents, classroom observations and interviews with teachers, board members, parents and students. The findings show that the educational contexts have different legal statuses and are governed at different policy levels (national vs. transnational), while sharing many structural constraints at the level of praxis, such as being based on voluntary participation, limited instruction time and inconvenient scheduling. However, the key actors navigate the constraints of each setting in different ways, thus pointing to distinctive differences between them. Ultimately, the study shows how both educational systems complement each other and serve important roles in supporting the maintenance and development of heritage language and culture in Sweden.