The subjective well-being (SWB) of older adult sojourners is a complex psychological phenomenon. This study employs a combined approach of partial least squares structural equation modeling (PLS-SEM) and fuzzy qualitative comparative analysis (fsQCA) to investigate the linear and nonlinear effects of motivation on the SWB of older adult sojourners. The results indicate that relaxation and decompression, wellness retreats, escape, and self-actualization motivations have a significant positive impact on the SWB of older adult sojourners. However, simple antecedent variables do not individually constitute the necessary conditions for high-level SWB; each variable requires a conditional combination with other factors to generate high-level SWB. Furthermore, this study reveals that nine different combinations of fsQCA consistently lead to high levels of SWB in older adult sojourners. These nine combinations can be categorized into five specific causal pathways, with the escape motivation serving as a core condition in each pathway. This study extends the research on senior residential tourism and offers practical insights for enhancing the competitiveness of senior residential tourism destinations.