There is a rising recognition of the crucial role self-care plays in managing heart failure (HF). Yet patients often have difficulties implementing ongoing self-care recommendations into their daily lives. There is also recognition of the importance of theory for successful intervention design, and understanding of key factors for implementation so interventions fit a given context. Local key stakeholders can provide valuable insights to help understand relevant context-specific factors for intervention implementation. This study sought to engage stakeholders to explore and determine relevant contextual factors needed to design and facilitate successful implementation of an HF self-care intervention in the German health care system. A ranking-type Delphi approach was used to establish consensus from stakeholders (i.e., clinicians, patients, policymakers/potential funders) regarding eight factors (content, interventionist, target group, location, mode of delivery, intensity, duration, and format) to adequately define the components and implementation strategy of the intervention. Seventeen participants were invited to participate in the first Delphi round. A response rate of 94% (16/17) was achieved and maintained for all three Delphi rounds. Stakeholder consensus determined that nurses specializing in HF are the most appropriate interventionists, target groups should include patients and carers, and the intervention should occur in an outpatient HF clinic, be a mixture of group and individual training sessions, and last for 30 minutes. Sessions should take place more frequently in the beginning and less often over time. Local stakeholders can help determine contextual factors that must be taken into account for successful delivery of an intervention. This enables the intervention to be developed and applied based on these factors, to make it suitable for the target context and to enhance participation to achieve the desired outcomes.