This critical review examines the transformative impact of integrating topology optimization and additive manufacturing (AM) on the design and production of transtibial prosthetic feet. By systematically surveying peer-reviewed studies published between 2010 and 2024, this work highlights how computational algorithms—such as SIMP, level-set, and evolutionary methods—can achieve mass reductions of 50–70% while maintaining safety factors above 1.5. Concurrently, AM technologies including FDM, SLS, and SLA faithfully reproduce complex, patient-specific geometries with deviations under 5% from finite element analysis (FEA) predictions. Material innovations span thermoplastics (PLA, nylon 66), advanced composites (CFRP, titanium lattices), and emerging smart materials (shape-memory polymers, piezoelectric composites), collectively enhancing energy return by up to 30% and fatigue life by more than 10⁵ cycles. Comprehensive validation—encompassing ISO 10328 static testing, dynamic fatigue trials, gait simulations, and wearer trials—confirms both mechanical integrity and user comfort, aided by integrated sensor systems for real-time performance monitoring. Regulatory and clinical pathways, including ISO 13485, FDA 510(k), MDR, and ISO 14155 guidelines, are discussed to facilitate translation into practice. Future research should focus on multicenter clinical trials, open-access design repositories, adaptive materials, and machine learning–driven predictive maintenance to propel patient-centered innovation in prosthetic care.