Despite evolution from the handicapped-access design of the 1960s to current universal design, society has yet to consistently implement socially inclusive and functionally and socially sustainable built environments for people with disabilities. This study has concentrated on deriving an effective inclusive-design learning framework for built-environment designers. Nineteen participants from five disparate realms (disability studies; environmental design; lived experience of people with physical and visual disabilities; occupational therapy; orientation and mobility; and social work) were interviewed over a 14-month period. Three rounds of interviews were conducted with each participant from each realm. A grounded theory research methodology was applied to elicit the in-depth tacit knowledge of participants who retained a mean average of 22.8 years in their respective realm. The result has been the discovery of a coalescing in disciplinary and lived experience theories, conceiving a new term: Environmental Design Transinclusive Learning Theoretical Approach Framework. This framework relies upon four dynamic, holistic, complex, and mutually interactive transinclusive learning dimensions of: (a) embodiment, (b) lived experience in environment, (c) transdisciplinarity, and (d) social sustainability—all interacting on a self-directed-learning and adult-education foundation. This vital discovery could well act as a catalyst for professional-cultural and emancipatory-learning shifts toward more socially inclusive design.