This paper draws on a case study from a larger research project which is concerned to explore what practitioners with a social justice agenda actually do when they have to translate their principles into the messy world of practice. The case study focuses on the perspectives of a consultant employed by an English urban local education authority whose role is to work with schools to help teachers identify and disseminate good practice relating to raising the achievement of black boys. The paper examines two kinds of tension that Jo has to navigate. The first is between different facets of justice. For instance, Jo's commitment to a more equal distribution of educational resources depends for its realisation on ethnic categorisation and monitoring and therefore collides with her commitment to forms of cultural recognition that challenge stereotypes and that validate the fluid and hybrid nature of young people's identities. The second kind of tension is that between, on the one hand, Jo's commitment to justice and, on the other, a policy and discursive context that is, in effect, often hostile to a justice agenda. The aim of the paper is to help achieve a detailed and grounded understanding of what combination of values are realisable in the real policy and practice settings within which Jo and others like her are working.