In recent years, Japan has witnessed the collapse of collectivism and the accompanying progression of individualization, which has led to a weakening of community ties, particularly intergenerational connections. Such weakening not only undermines local communities but also adversely affects individual well-being. This study explores kikigaki (life-story listening and writing) as a relational tool, focusing on how it can foster intergenerational connections and contribute to community building. In this study, kikigaki is defined as a process in which one listens to another's life story, distills its essence, documents it in writing, and shares it with others. Action research was conducted in collaboration with a high school, utilizing its "Inquiry-Based Cross-Disciplinary Study" curriculum. After receiving training in kikigaki, high school students were paired with local residents and engaged in listening to and documenting their life experiences. Data were collected through interviews and questionnaires to examine the impact of kikigaki on the relationships between students and residents, and to explore how these relationships could be extended to community development initiatives. The findings are discussed within the framework of Gergen's theory of co-action, highlighting the potential of kikigaki as a practice for intergenerational relationship-building and community well-being.