Background <p>The increasing proportion of older adults globally poses challenges to mental well-being, as aging is often accompanied by a decline in positive emotional experiences (PEE) and life satisfaction (LS). While previous studies have explored the relationship between basic psychological needs satisfaction (BPNS) and mental health in older adults, the role of life satisfaction as a mediating factor in the relationship between BPNS and daily emotional well-being remains underexplored.</p> Objective <p>This study aims to investigate the relationship between BPNS and PEE among older adults and to examine the mediating role of LS. By employing the Experience Sampling Method (ESM) through a mobile application, the study provides real-time data on the emotional experiences of older adults.</p> Methods <p>The study recruited 33 older adults (mean age = 63.24&#xa0;years, SD = 5.92) who reported their daily emotional states through a mobile application three times a day for nine days. A total of 811 valid records were collected. Positive emotional experiences were assessed at the experience level, while BPNS and LS were assessed at the individual level. Data were analyzed using Hierarchical Linear Modeling (HLM) to examine the mediating effect of LS between BPNS and PEE.</p> Results <p>Results revealed that LS significantly mediated the relationship between BPNS and PEE. Older adults with higher BPNS reported higher LS, which in turn enhanced their daily PEE. This finding supports the hypothesis that BPNS positively influences PEE through improved LS.</p> Implications <p>The study highlights the importance of fostering BPNS to improve LS and daily positive emotions among older adults. The use of mobile applications to capture dynamic emotional states offers a practical and scalable approach for psychological research, particularly in aging populations. Further interventions could focus on enhancing BPNS to promote emotional well-being in older adults.</p>