The central aim of this research is to investigate the underlying mechanism between parental involvement and externalizing problem behaviors in Chinese rural adolescents. While earlier studies have investigated this link, the pivotal influences of peer relationships, mental health, and problematic social media use have not been thoroughly addressed. In this analysis, 3157 rural Chinese adolescents aged 13–19 years participated by filling out an anonymous self-report questionnaire. Our findings revealed that: (1) parental involvement acted as a protective factor against the emergence of externalizing problem behaviors; (2) both peer relationships and mental health served as mediators in the connection between parental involvement and externalizing problem behaviors; (3) parental involvement indirectly influenced externalizing problem behaviors through the sequential mediation of peer relationships and mental health; and (4) as problematic social media use escalated among rural adolescents, the protective impact of parental involvement on externalizing problem behaviors weakened. Building on these findings, the study has identified possible causes and suggested practical interventions to mitigate externalizing problem behaviors among rural adolescents.