Background:Based on the technologies of applied behavior analysis and person-centered planning, positive behavior support is a process for designing and implementing proactive behavioral interventions with the goal of positive lifestyle changes.Participants:The two adolescents who received the intensive, longitudinal, multicomponent intervention had experienced escalating behavior challenges over several years after brain injury in early childhood.Main Outcome Measures:Quantitative data included episodes of aggression and property destruction. Qualitative data included intensity of supports, family involvement, peer relationships, medication regime, vocational status, educational status, community access, and self-help skills.Research Design:A long-term, natural-environment, case-study method was used.Results:The targeted challenging behaviors were reduced to zero. In addition, the participants' domains of activity increased and self-management improved even as supports were systematically withdrawn.Conclusions:These results illustrate the potential for successfully treating extreme chronic behavior disorders after childhood brain injury.