Objective: This study is an evaluation of patients in mental health care who have undertaken treatment with an integrated family approach. The treatment focuses on the mental disorders of patients, their role as parents, the development of their young children, and family relationships. The treatment was conducted by professionals from an adult and a child mental health service in the Netherlands. The aim of the study was to identify the key elements and processes of this approach in order to develop a theoretical model. Background: Parental mental disorders have an impact on parenting and child development. To stop detrimental cascade effects and prevent parents and children from being caught up in the intergenerational transmission of psychopathology, a family approach in mental health care is needed. Methods: A qualitative design was adopted using thematic analysis. Data were collected through 18 interviews with patients. The themes in the interviews were which outcomes the patients experienced and which key elements of the treatment contributed to these outcomes. Results: In general, patients were satisfied with the treatment offered. Improved outcomes were within the domain of the family, the parent-child relationship, individual symptoms, and the functioning of the parent and the child. Patients mentioned six key elements of success in treatment: focus on the whole family, flexible treatment tailored to the situation of the family, components of the whole treatment reinforcing each other, multi-disciplinary consultation among involved professionals, a liaison between adult and child mental health services, and attention to the social and economic environment. Conclusions: According to the majority of patients, treatment with an integrated family approach in mental health care is of value for themselves, their children, and family relationships, especially the parent-child relationship.