This study evaluates a school-based primary prevention intervention designed to promote adolescents’ coping in the immediate aftermath of war exposure in Operation Cast Lead. Participants were 179 adolescents from two demographically similar schools in Ashkelon in south Israel. The intervention incorporated two previously proven resilience factors—mobilization of support and self-efficacy. In a repeated measures design, the study assessed pre- to post-test changes in intervention (n = 94) and control (n = 85) conditions among adolescents exposed to high or low political life events (PLE). Findings showed significant pre-test differences in self-efficacy and psychological symptoms between participants with low and high PLE. For both PLE groups, the intervention strengthened support mobilization and self-efficacy and reduced psychological distress and emotional symptoms. Findings reinforce the importance of offering appropriate evidence-based interventions for school staff to restore security and well-being to adolescents in a crisis context immediately following war. Despite the apparent return to a school routine after war, school staff should be aware of the risk to youth for development of psychological symptoms and disorders, and the need for preventative intervention.