Project Safe Neighborhoods (PSN) is an increasingly popular violence and gun crime prevention program that aims to identify prolific violent offenders and deter or incapacitate them from offending. While PSN programs generally show moderate effects on violence and gun crime reduction, questions remain about the magnitude and duration of effects given the heterogeneity in treatment applications across PSN programs. This study presents a quasi-experimental evaluation of a cutting-edge PSN initiative on violence and gun crime in Tampa, Florida over a 6-year period. Results indicate that PSN was associated with a 24.4% raw reduction in violence (d = −0.16) and a 24.0% reduction in gun crime rates (d = −0.22) for the treatment agency, while the control groups saw much smaller decreases in violence and gun crime over the same time period.