Background Primary care practitioners worldwide are urged to promote dementia risk reduction as part of preventive care. To facilitate this in Australian primary care, we developed the Umbrella intervention, comprising a waiting room survey and patient information cards for use in consultations. Educational and relational strategies were employed to mitigate implementation barriers. Methods In this cross-sectional, non-randomised implementation study within the South East Melbourne Primary Health Network, we employed mixed-methods outcome evaluation. Antecedent outcomes (acceptability, appropriateness, and feasibility) and actual outcomes (adoption, penetration, and fidelity) were assessed from the perspective of primary care practitioners and patients. Results Five practices piloted the intervention and implementation strategies, including 16 primary care practitioners engaging with 159 patients. The Umbrella intervention was deemed acceptable, appropriate, and feasible, but penetration was limited. Approximately half of eligible primary care practitioners used the intervention, with moderate fidelity. Engagement with implementation strategies was similarly limited. While most strategies were well-received, improvements in online peer discussions and staff readiness were desired. Conclusions The Umbrella intervention is a viable approach to promoting dementia risk reduction in Australian general practice, supported by educational and relational strategies. Stakeholder-informed refinements to enhance uptake are recommended before advancing to a definitive trial.