Structured aftercare programs are implemented to facilitate the transition from rehabilitation centers to patients' home environments. Taking the program GeRas as an example, this paper aims to evaluate the influence of patient-related factors on the implementation of the geriatric aftercare program GeRas from patients' and providers' perspectives. To capture patients' and providers' perspectives, qualitative interviews were conducted using a semi-structured interview guide. The analysis was inductive-deductive and based on the thematic analysis by Braun and Clarke and guided by Domain IV of the CFIR. 16 participants (10 patients, 4 providers, 2 family members) were interviewed from May 2023 to November 2023. Patient-related factors were perceived as an important aspect during the implementation of the GeRas program. The results were allocated to the four Constructs of Domain IV of the CFIR (Motivation, Opportunity, Capability, Needs). Especially patients' intrinsic motivation, social environment, and physical capabilities seemed to be crucial for successful implementation. While extrinsic motivation can mitigate missing personal capabilities, it cannot replace the presence of intrinsic motivation and capabilities. The results showed that patient-related factors are interlinked. The relevance of patient-related factors during the implementation of the GeRas program shows that such programs must consider these factors during intervention planning.