This paper presents an analysis of an interaction between a student with profound intellectual impairment and his teacher. To develop understandings of the participatory experiences of people with profound intellectual impairment we need to relinquishment pre-emptive categorizations such as "profound intellectual impairment". Such categorizations by researchers and others produce hypothetical mental and social states and anticipated displays. This paper examines the co-ordinated details of an actual interaction. The work reported in this paper has been analytically and theoretically challenging because the student is non-vocal. Conversation analysis is used to illustrate, describe and interpret how a student with profound intellectual impairment and his teacher set about the business of constructing their interaction during a classroom activity. Through accounts of action, participants make sense of their own and each other's actions. This paper demonstrates that this is also the case even when one participant has a profound intellectual impairment. Recognition and appreciation of the social agency of a person with profound intellectual impairment demands a reimagining of what counts as participation.