This study evaluates the process of implementation and the impact of a focused deterrence-based strategy on group member-involved gun violence in Malmö, Sweden. This is the first attempt to implement and evaluate a focused deterrence-based strategy to combat gun violence in a Swedish as well as a Nordic setting. The study presents an overview of the entire project, aiming to describe both the implementation and its impact, while also identifying specific areas for further investigation in more specialised studies. The planning of what would later be called Ceasefire Malmö began in 2017 after an upsurge of gun violence that peaked in 2016–2017. We followed the process of planning and implementation until December 2022. The process evaluation finds that it was possible to implement the strategy in a Swedish setting, but also identifies challenges that need to be addressed in future implementations. The results further show that, in line with much of previous, mainly American, implementation studies, gun violence decreased following implementation. Results from this evaluation are, however, not fully conclusive and should be interpreted with some care. The evidence base for interventions to counteract group-related violence is limited and without more knowledge authorities risk implementing strategies with no proven effect, risking lives and wasting resources. As such, this evaluation makes a valuable contribution to policy makers, providing them with guidance on how to implement focused deterrence-based strategies in a European context and the effect of such strategies.