In 2002, Martin became Commissioner of the New York City Department of Probation. A year later, he was appointed to simultaneously serve as Commissioner of the NYC Department of Correction. As Correction Commissioner, Horn rebuilt morale, accountability, and integrity following a series of highly publicized scandals. He reduced suicides and cut jail violence in half. Under his leadership, several conditions of confinement lawsuits were satisfactorily resolved. Horn reduced the introduction of drugs into jail and created the largest and most ambitious jail reentry program in the nation. He re-engineered the intake process to ensure all inmates were properly screened for vulnerability, possess the documents needed to work upon release, and created transitional job opportunities for persons released from jail.
As Probation Commissioner, Martin focused on high-risk offenders, improving the delivery of treatment for addiction to alcohol and other drugs, employment of offenders, and streamlining the probation violation process. As a result of his efforts, recidivism among adult probationers dropped faster than in any other jurisdiction in New York State. His “Project Zero” effort led to a 70% reduction in the placement of juvenile delinquents and a tripling of the number of alleged delinquents diverted following arrest.
Horn has served as co-chair of the American Bar Association Corrections Committee and was a member of the Commission on Accreditation for Corrections. He is a recipient of the Michael Francke Award, the highest honor bestowed by the Association of Corrections Administrators (now Correctional Leaders Association).