This article describes a lawsuit that created a right to discharge planning for people with psychiatric disabilities leaving New York City jails. The article, written by one of the attorneys representing the plaintiff class, describes Brad H. v. City of New York, uses affidavits and records gathered during the litigation to highlight essential components of mental health discharge planning in jails and prisons, and argues that a so-called transinstitutionalization of the rights of incarcerated people with psychiatric disabilities through litigation may be one strategy for reducing criminalization of mental illness.