The economic, environmental, and social impacts caused by the extensive resource consumption and harmful emissions from the metal manufacturing industry should be lowered through innovative sustainable manufacturing strategies. This study aims to investigate the techno-eco-efficiency performance of metal additive manufactured (AM) parts in comparison with metal subtractive manufactured (SM) parts to determine the technical, economic, and environmental performance as a decision support tool for selecting the most techno-eco-efficient manufacturing method. In this study, a novel metal extrusion AM technology has been used to create a centrifugal semi-open pump impeller in 316L stainless steel material. The technical feasibility of the impellers has been determined by evaluating the geometry, build material, mechanics, morphology, and functional performance of the impellers. The eco-efficiency performance of technically feasible impellers was evaluated through environmental life cycle assessment, life cycle costing, and portfolio analysis. The findings reveal that AM impeller’s higher normalised costs (43.8%) have been offset by its lower normalised environmental impacts (54.6%) compared to the SM impeller. The centrifugal semi-open pump impellers made by the novel metal AM technology are technically feasible, cost-effective, and environmentally friendly compared to their SM counterparts.