In the field of geriatric psychology studies, research indicates that volunteering contributes to seniors’ quality of life. It is supposed to have cognitive and relational benefits (acting as a barrier against intellectual decline and social isolation), and benefits for self-esteem. However, few studies delve into the psychosocial processes underlying volunteering activity and its potential for development. By adopting a sociocultural approach in psychology, which focuses on the activity as the unit of analysis, social interactions, semiotic mediations, and processes of meaning-making in the lifespan (Grossen et al., 2021, Learning, Culture and Social Interaction, 37, 100478; Muller Mirza & dos Santos Mamed, 2021, Dialogical approaches and tensions in learning and development. At the frontiers of the mind. Springer. https://link.springer.com/book/10.1007/978-3-030-84226-0 ), we assume that we can better understand the potential contribution of a volunteering activity for the development of people getting older. Using an original method of data production inspired by phenomenology and sociocultural psychology, the narrativo-explicative interview (Cesari Lusso & Muller Mirza, 2022, Expliciter, 133, 1–28), which aims to document the activity carried out by the volunteers, we analyze four interviews conducted with seniors regarding their engagement (Fassa et al., 2018, Bien vivre sa retraite avec les autres. Engagements, compétences et qualité de la vie à l’ère du lifelong learning. Fondation Leenaards). We will show that activities they undertake elicit psychological reorganizations across multiple interdependent dimensions, including cognitive, relational, and identity-related aspects. Under certain circumstances, the meaning of experiences and competencies elaborated in past contexts is reshaped and provide a space for elaborating a possible future.