Based on substantial preliminary evidence, a four-year Gang Violence Reduction Project has demonstrated its effectiveness in terms of process and outcome. An innovative approach in the prevention and control of a serious gang violence problem was based on key interrelated strategies of community mobilization, social intervention, suppression, opportunities provision, organizational development, and targeting. A team of community youth workers, tactical police officers, adult probation officers, and representatives of a neighborhood organization operated under the aegis of the Chicago Police Department. Of special interest was the interrelated practice roles of police tactical officers and community youth workers, many of whom were former gang members.