BACKGROUND: Severe malaria poses a significant challenge to under-five children in Malawi, leading to high rates of hospitalization and mortality. The World Health Organization has recently recommended post-discharge malaria chemoprevention (PDMC) as a preventive strategy for under-five children with severe anaemia in malaria-endemic regions. In response to this recommendation, Malawi's Ministry of Health (MoH) plans to implement PDMC nationwide. To facilitate effective implementation, the MoH has partnered with the Training and Research Unit of Excellence (TRUE) to conduct PDMC delivery trials to gather evidence for practical implementation in Malawi and similar settings. A key component of this initiative involved the MoH leading the co-design workshops with key stakeholders to foster collaboration, spur innovation, and develop user-centred strategies. This collaborative effort aimed to investigate optimal PDMC implementation strategies to guide the scale-up in Malawi and contribute to policy-making processes that enhance transparency, accountability, and ownership. METHODS: This participatory action research occurred in the Salima district, Malawi, from 11 to 12 May 2023. Two co-design workshops were utilized, involving policymakers (n = 15), healthcare providers (n = 8), and prospective users (n = 2). The approach consisted of two stages. First, separate information-gathering sessions were held with policymakers, healthcare providers, and prospective users. Second, a structured discussion was facilitated, allowing collaboration between policymakers, healthcare providers, and prospective users to develop strategies for delivering and integrating the intervention. Discussions were audio recorded, transcribed verbatim, and manually analyzed using a thematic approach. RESULTS: The inductive analysis yielded four overarching themes from the data. These key themes are PDMC adaptability, trialability, implementability, and sustainability. Stakeholders recommended adopting PDMC in Malawi, with health facilities as the optimal delivery option, ensuring that discharged children receive dihydroartemisinin-piperaquine doses for three months. PDMC aligns with existing systems, offering integration opportunities for managing childhood illnesses. However, gaps in policy development, approval, and health system strengthening-including supply chain, monitoring, evaluation, and follow-up-must be addressed to ensure PDMC's sustainability. CONCLUSIONS: The co-design results indicate stakeholders' willingness to adopt and implement PDMC in Malawi. However, there is an awareness of the challenges that must be addressed to facilitate PDMC's successful implementation and sustainability.