Recovery from mental illness and co-occurring substance use disorders, as well as increased public safety and reduced rates of recidivism, are possible when communities take action by forming cross-systems partnerships and identifying a mutually identified set of action steps to promote continuous, appropriate, and integrated treatment services in the community for justice system-involved citizens. The path to positive systems-level change is through effective cross-systems collaboration, the key concept upon which the ACTION approach is based. The ACTION approach is a unique approach for stimulating community change that goes beyond classic training or cross-training to promote cross-systems collaboration and coordinated integrated treatment methods for people with co-occurring disorders in contact with the criminal justice system. The ACTION approach demonstrates that positive systems change is possible through education about the fundamental principles and culture of each of the mental health, substance abuse, and criminal justice systems, and facilitated strategic planning to assist communities in developing a concrete action plan. Approximately 900,000 people with active symptoms of serious mental illness are booked annually into United States jails. Of these, about three-quarters have a co-occurring substance use disorder. When these people return to the community they have multiple, complex and interrelated treatment needs, which are sometime exacerbated by release into the community. This paper presents an approach to cross-systems collaboration among the criminal justice, mental health, and substance abuse systems to promote recovery of incarcerated people with co-occurring disorders reentering the community through education, facilitated strategic planning, and followup technical assistance. Tables, note, references