3D printing is rapidly developing to customize products to the specific requirements of the customers. This paper explores the effects of 3D printing on a basic remanufacturing supply chain, which comprises a manufacturer and a retailer. By constructing a Stackelberg game model, we investigate how supply chain participants should make investment decisions regarding customized remanufactured products to optimize profit, focusing on two models of customization: one implemented by the manufacturer and the other by the retailer. We identify the economic and competitive scenarios that support either firm’s adoption of 3D printing and demonstrate that both firms can enhance their profitability in certain 3D printing contexts. Our results illustrate the relationship between the adoption of 3D printing, consumer preferences for customization, and the remanufactured product market. Notably, we find that having 3D printers located at the retailer typically yields the highest profit outcomes for both the manufacturer and the retailer. Additionally, we evaluate how various factors affect the level of customization effort, demonstrating that in both the manufacturer-customized and retailer-customized models, a decline in consumer preference for customization results in reduced effort and overall profit. Finally, through numerical analysis, we illustrate how the decisions made by manufacturers and retailers are influenced by the customization sensitivity coefficient and the associated costs. This study provides guidance for companies looking to integrate 3D printing and remanufacturing technology into their strategic planning.