Depression is a leading contributor to the global burden of disease and a significant problem in primary care, where it is typically identified and managed. Stepped care approaches are recommended but difficult to implement in routine care, due in part to a lack of effective tools to guide GPs in matching intervention intensity to patient need. Therefore, a clinical prediction tool was developed, which was embedded into a person-centred e-health platform, that matches depression management options to symptom severity prognosis. This randomised controlled trial showed using this platform results in greater improvement in depressive symptoms at 3 months compared to usual care. This approach could be implemented in routine care to support more efficient and effective depression care without adding to GPs’ workload.