Cultural historical activity theory perspectives are drawn in this paper to realize collective transformative agency and the externalization of individual student identity, with students seeking personalized assistance from their teacher while learning mathematics at a grade eight classroom in Sweden. Even as teacher-researcher collaboration and the execution of a five-task formative intervention resulted in realization of transformative agency, the externalization of identity gained from students working with peers and being led in instructional activity that was practical and meaningful to their lives. While the externalization of identity by individual students during their learning resulted in transformative agency realized at the collective level in their teacher's instructional practice, the role of knowledge within such a practice was found to be just as vital in line with the construct of Transformative Activist Stance.