In the intersection of the aging and information era, the development of digital aging significantly influences the well-being of older individuals. Given the divergent findings in various studies exploring the effects of social media use on mental health, this study specifically examined the impact of forwarding, a prevalent social media behavior among older individuals, focusing on the effects of use intensity on their subjective well-being (SWB) and the specific mechanisms involved. A total of 323 Chinese older adults completed the questionnaire. SPSS along with Hayes Process Models 4 and 7 was employed to test the hypotheses. The results indicated that social media forwarding intensity significantly and positively predicted SWB of older adults. This association was partially mediated by perceived social support (PSS) and self-esteem. Gender served as a moderator, highlighting that the positive predictive effects of forwarding intensity on PSS and self-esteem were more pronounced for older men than for older women. Further, the findings confirmed the existence of the moderated mediating effect such that the impact of forwarding on SWB was mediated through both PSS and self-esteem for older men, while, for older women, it was solely mediated by PSS. This study revealed the positive impact of forwarding, a user-friendly social media function, on the well-being of older adults and elucidated the specific mechanisms through a moderated mediation model. In light of these findings, we propose customizing the development of age-friendly social media functions to address the diverse psychological needs of older adults, taking into account gender differences. These findings may offer valuable insights for constructing digital age-friendly platforms and fostering active aging development.