Introduction Optimising function is critical for healthy ageing, although health and care systems routinely lose the crystallised expertise of older professionals at retirement, particularly in Design–Built Environments (DBE) and Health Systems and Care (HSC) leadership. This occurs despite evidence that age inclusive workplaces, multigenerational teams and senior entrepreneurship can enhance performance, participation and well being. This paper outlines a conceptual framework for preserving and mobilising third age wisdom in these domains to support functional ability in older adults. Methods A documentary and narrative review was undertaken on age inclusive workplaces, age diversity, senior entrepreneurship and later life self employment, informed by Baltes’ Selective Optimisation with Compensation model and Inclusive Workplace Theory. These findings were synthesised into a preliminary model for framing modular digital Third Age Time Capsules (TATCOs) that capture late-career and retired experts’ practice-based knowledge. Results The review identifies three critical mechanisms through which third age expertise can optimise function: (1) design principles for buildings and environments that enable mobility, cognitive orientation and social participation; (2) leadership and organisational practices that prioritise functional outcomes in assessment, care pathways and resource allocation; and (3) later life career tracks that re engage older experts as mentors, consultants and senior entrepreneurs. These mechanisms are integrated into a prototype framework for DBE and HSC digital time capsules. Conclusions Preserving and redeploying DBE and HSC wisdom from older professionals offers a scalable strategy to optimise function at individual and system levels. Future research will co-design and pilot sector-specific TATCOs with stakeholders to assess feasibility and impact, with potential extension to other industries.