This article considers how one may integrate ethnographic data generation with research questions and an analytic framework that are strongly theoretically informed by Cultural Historical Activity Theory (CHAT). Generating data through participant observation of school-based, student teacher education activity and interviewing all those involved in initial teacher education (ITE) in one school over an academic year allowed research questions to be addressed about student teachers' learning opportunities in the school setting. Although purposively generating data iteratively, the research uses CHAT as a descriptive heuristic to explore whether participants share understandings of the object and tools of school-based ITE activity systems across four subject departments. This article illustrates in relation to one of the subject departments a complex analysis of teacher education and development that does more than put the individual student teacher at the centre of the frame as they learn "on the job". (Contains 1 figure.)