This research investigates consumer reactions to personalized upcycling, which refers to a novel form of commercial upcycling whereby a company transforms a consumer’s own waste materials into an upcycled product for the same consumer (e.g., transforming a consumer’s old jeans into a weekend bag for them). A field study and six controlled experiments show that personalized upcycling elicits more positive consumer reactions compared to made-to-stock upcycling (i.e., upcycled products made from waste materials that a company generates itself or receives from its suppliers) and other green products, such as recycled products or secondhand products. This effect occurs because consumers already own the waste materials (i.e., what is mine) before they are transformed into a personalized upcycled product for them, which helps them see the trait of environmental consciousness embodied by personalized upcycled products in themselves (i.e., what is me)—referred to as pro-environmental activation. Finally, we investigate a socially important downstream consequence of personalized upcycling and demonstrate that the higher level of pro-environmental activation that consumers derive from personalized upcycling leads to enhanced pro-environmental behavior in areas beyond the product in question.