Research on teachers’ knowledge and beliefs has grown big in recent years. Thelarger parts of these fields are built on acquisitionist interpretations of humanfunctioning. We explore the potentials of a participationist framework forunderstanding the role of the teacher for emerging classroom practices. Theframework is built on social practice theory and symbolic interactionism and adoptsa processual approach to understanding the role of the teacher. We use theframework in a qualitative study of two teachers with different prior experiences. Thestudy suggests that the framework has some potential and sheds light on the dynamicrelationships between the teacher’s engagement in the practices of the mathematicsclassroom and other, personally significant, past and present ones.