A dominant discourse on "scaling-up" small-scale innovations based on a limited number of successful classroom trials pervades the educational literature. We view this discourse as insensitive to the professional work of teachers and the human side of school change. Our research investigated how teacher professional development could be conceived and conducted to support take up of digital game-based learning in the context of a 3-week social studies unit on governance and citizenship. Students played a mobile game in their own time. In the classroom, teachers enacted dialogic pedagogy to facilitate students' meaning-making of their gameplay experience. Our findings indicate that teacher identity, constituted by their interwoven knowing-doing-being-valuing is central to any effort to scale pedagogical and technological innovation. We modified our original model for the appropriation of innovation uptake by teachers to one that places teacher identity as the centrepiece of the model and cornerstone in "shifting" teacher practice.