This study investigates the interplay among identity, language, and culture of six heritage language (HL) teachers at a Greek school in the German-speaking part of Switzerland. It applies the concept of "participative multilingual identity construction" and argues that in order for teachers to provide agency and opportunities to their students to engage in (multilingual) identity education, they first need to acquire critical linguistic awareness and sociolinguistic knowledge themselves. The study found that most teachers do not identify as "multilingual" despite their competences and daily social practices in multiple languages, but rather base their identifications on their first language-Greek-with certain local influences. It also demonstrated that teachers' understanding of their role, responsibility, and position within the HL teaching context, their own migration experiences, and ideologies regarding heritage and local languages and cultures influence their teaching practices and students' construction of their multilingual identity. This contribution advocates the institutionalisation of HL-specific teacher preparation with a focus on identity, multilingualism, and community experiences to recognise the increasing heterogeneity of twenty-first-century classrooms. It ultimately seeks to advance the normalisation of linguistic and cultural diversity, the deconstruction of pernicious language hierarchies and ideologies, and the promotion of equity and social justice.