Social sustainability is essential in Public–Private Partnership (PPP) aged care projects, as it ensures that the private sector prioritises improving stakeholders’ quality of life alongside profit generation. This study explores how to structure PPP projects to effectively achieve social sustainability. The research adopts a prescriptive theorising approach, using predefined social sustainability goals as a basis for evaluating their realisation. A single case study was conducted on an aged care PPP project in China. The case analysis confirms that achieving social sustainability is vital for PPPs, requiring sustainable processes to ensure the delivery of sustainable services. This research contributes to understanding how social sustainability can be achieved in PPP aged care projects, with a particular focus on the achievement process. By concentrating on aged care, the study demonstrates how PPPs can be structured to deliver high-quality care services and proposes a structured method for analysing and achieving social sustainability by integrating prescriptive theorising with backcasting.