Background: Severe and persistent conduct problems in children during the primary school years are associated with school exclusion, increased risk of delinquency and early substance abuse. Method: Literature reviews and consultation with experts in the field were used to better understand the factors that contribute to severe and persistent conduct problems and to identify the principles and potential methods to be included in a new intervention. Results: Grounded in an ecological perspective, an innovative, multimodal intervention, the Helping Families Programme, has been developed. It uses a modular approach to systematically address parent behaviour, cognition and emotion across five key risk factor domains: parental mood and dysregulation; parent-child, family and school relationships; substance misuse; social support and networks; and managing life events and crises. Conclusion: Initial piloting of the Programme has offered early support for the potential value of the underlying principles and methods of the Programme.