All too often young people are excluded in practice from the general policy and professional consensus that partnership and participation should underpin work with children, young people and their families. If working with troubled and troublesome young people is to be based on family support, it will require not only the clear statement of that policy but also demonstration that it can be applied in practice. Achieving that involves setting out a plausible theory of change that can be rigorously evaluated. This paper suggests a conceptual model that draws on social support theory to harness the ideas of social capital and resilience in a way that can link formal family support interventions to adolescent coping. Research with young people attending three community-based projects for marginalized youth is used to illustrate how validated tools can be used to measure and document the detail of support, resilience, social capital and coping in young people's lives. It is also suggested that there is sufficient fit between the findings emerging from the study and the model to justify the model being more rigorously tested.