In the 1930s, children who were violent, depressed, psychotic, or suicidal would likely have been labeled delinquent and sent to a custodial training school for punitive treatment. But starting in the 1940s, a new group of institutions embarked on a new experiment to salvage and treat severely deviant children. In the process, psychiatrists, psychologists, and social workers at these residential treatment centers (RTCs) made visible, and indeed invented, a new patient population. This article uses medical literature, popular media, and archival sources from several RTCs to argue that staff members created what they called the “emotionally disturbed” child. While historians have described the identification of the mildly “troublesome” child in child guidance clinics, I demonstrate how a much more severely ill child was identified and defined in the process of creating residential treatment and child mental health as a professional enterprise.