Children and their parents who become homeless constitute a group of families with a complex range of social care and health needs, including mental health difficulties. In response to this, a local authority housing department established a family support team (FST) that provides assessment and detection of a range of problems, support to parents and children, parenting interventions for child behavioural problems, liaison with other agencies, and referral to specialist services when appropriate. The aim of this study was to establish the perceptions of parents and staff on their experience of the service, and ways of improving it in the future. The study adopted a developmental evaluation approach and used multiple methods, including in-depth interviews with families; diaries; reflective activities; participatory learning and action; and observation of the FST. The study mapped the innovative service and captured the range of skills in the team and the complexity of agencies the team interacted with. It also identified areas for further development in terms of the mental health needs of children and parents who have become homeless.