["Child &Family Social Work, EarlyView. ", "\nABSTRACT\nGuided by problem behaviour theory (PBT), the present study aims to identify how the family‐level influence of parental drinking (PD), as a central element in the behavioural system, affects vulnerable children's problematic Internet use (PIU), whereas other individual and environmental factors like resilience and school life may influence its intensity and duration. Our research was embedded within a comprehensive psychological health census covering the entire population of vulnerable children in Hubei Province, China. This study employs a quantitative research methodology and utilizes propensity score matching (PSM) for analysis. In accordance with PBT, our study focused on revealing the potential negative relationship between PD and the PIU of vulnerable children, a critical area given the family context. We also found that a more positive school environment may be more strongly associated with PIU. The findings reveal a comprehensive framework demonstrating that the influence of PD on PIU among vulnerable children extends beyond direct behavioural pathways, encompassing risk modulation mechanisms within personality and broader environmental systems, particularly highlighting the family's role as a foundational system. Practically, the study calls for integrated family–school interventions, highlighting the need for targeted and coordinated support to reduce PIU among vulnerable children.\n"]