Aggression, conflict and restrictive practices present complexities in acute mental health services, as do implementing service changes to reduce them. Existing published literature needs to offer more high‐level guidance on the effectiveness of these service changes and their associated implementation factors. As a result, an overview of systematic reviews was undertaken to identify (i) nonpharmacological interventions to reduce conflict, aggression and restrictive practices in acute mental health settings, and (ii) their effects across different clinical outcomes. A parallel re‐extraction from primary studies was then utilised (iii) to identify factors influencing successful intervention implementation. Of 124 articles sourced from nine databases and registries, four reviews were retained for the final analysis, using the direction of effect and tabular and narrative summaries. These reviews included programmes or interventions focused on inpatient adolescent, adult and older adult populations. They reported on alternative containment strategies, risk assessments, Safewards, sensory rooms and equipment, Six Core Strategy–based interventions and staff training. The overview found that a combination of interventions intended to improve relationships and reduce interpersonal conflict may help reduce aggression, conflict and restrictive practices. At the same time, stand‐alone staff training and sensory rooms and equipment may have mixed effects. The quality of the evidence linking these interventions to reductions in aggression, conflict and restrictive practices is limited. Successful implementation hinges on multiple factors: intervention characteristics, preparation and planning, evaluation and monitoring, outcome interpretation, stakeholder involvement/investment, staff‐related factors and contextual factors. Any implementation initiative may benefit from using pragmatic and complexity‐informed research methodologies, including integrating meaningful involvement with service users, peer workers and culturally diverse groups.