The degree of involvement and roles of non-designers has grown in co-design research. Within this, the “transition” from being a supporter of designers and planners to being an active participant in the design process can be a focus for the field of community development from the perspective of achieving sustainability and autonomy in the design community. However, there are various practical barriers, such as a lack of leadership for projects, the fact that predetermined project timelines do not align with complex community challenges, and how the framework required for this transition has yet to be found in its entirety. This paper examines four years of community development in Inuyama City, Aichi Prefecture, Japan, which can be considered as having achieved autonomy and sustainability, focusing on the relationships between human, temporal, and physical environmental factors. The results show that for the multiple people involved in the project, activities have become known as “life projects,” where participants find purpose in their lives, and a “live-project” that develops in response to changes in the situation, generating autonomous and sustained involvement for participants. In so doing, we bring to light individual thoughts and objects that are subject to everyday change and thus form important starting points in this research. It displays the limitations of the design project concept, which is still dependent on planned problem-solving based on predicted causal laws. At the same time, it shows that a deeper sociological and anthropological analysis is needed to discuss the design process.