The aging of Japanese society will inevitably restructure Tokyo’s spatial organization in the coming decades. Population loss will manifest itself unevenly, being most dramatic in peripheral areas—where ca. 87% of Greater Tokyo Area’s population lives—triggering a gradual spatial restructuring. Several scholars have tackled this issue from a geographical and planning perspective. From an architect’s viewpoint, such researches build a theoretical foundation upon which a more concrete investigation should be done, since the question of how liveability at the architectural and urban design scale could be tackled remains an open one. This paper focuses on one representative case study: Tama New Town, some 30km west of Tokyo Station. The emphasis is on four liveability factors relating to urban morphology, embedded in a wider socio-economic context: density/compactness, diversity of uses, walkability and green/water space. The significance of the research is threefold. On a theoretical level, we have assessed how urban design physical factors impact liveability in Tokyo’s peripheral areas. On a methodological level, we have tested workable methods that can be used by architects and urban designers to analyze neighborhood liveability in both quantitative and qualitative terms. On a practical level, we have provided new data and information about Tama New Town for the use of local municipalities and groups, suggesting strategies to address existing problems and highlighting potentials to be exploited.