In this paper we argue for an approach to professional development which supports teachers to engage in sustained intellectual inquiry and to investigate the conditions in their classrooms that might make a difference for students at risk of not succeeding at school.  We focus on the work of one primary school teacher involved in the research project Teachers investigate unequal outcomes in literacy: Cross generational perspectives and explore the effects that redesigning her literacy curriculum had on her professional identity and the literacy outcomes for one of the children in her class.  We suggest that the principles of building theory and practice, positioning teachers as agentive, and making a space for teachers to bring new ? and renewed ? professional knowledge to their work are principles of practice that energise and sustain teachers and their day-to-day classroom work.  Such principles deserve attention, particularly at a time when teacher quality and professional standards are in the minds of policy makers.