It is widely believed that younger generations are at the forefront of sustainability efforts. Given the significance of fostering greater consumer participation in sustainable consumption, this perception prompts an intriguing question: If consumers associate sustainability with younger individuals, can simply instilling a sense of youthfulness increase their engagement in sustainable consumption, regardless of their actual age? Building upon previous research on subjective age—that is, how old one feels—and consumer identity, we propose that consumers will gravitate towards sustainable products when they feel younger than older. This is because such products align well with their perceived age identity, creating a perception of fit. The findings across three studies provide converging evidence that simply making consumers feel younger can result in an increased preference for sustainable products. Study 1 demonstrated that feeling younger increased the selection of more sustainable products over less sustainable ones. Study 2 showed that this effect is mediated by the perceived fit. Study 3 further supported the underlying mechanism by revealing that the focal effect was mitigated when the association between sustainability and younger age was weakened. Study 4 replicated the focal effect in a consequential choice setting. Finally, Study 5 confirmed the proposed effect by using trait subjective age as a predictor.