Heart valve disease remains a significant global health burden, with an estimated 290 million people affected worldwide. Prosthetic heart valves have become essential therapeutic options, with mechanical valves offering superior durability compared to biological alternatives, though requiring lifelong anticoagulation. Since the inception of mechanical heart valves, these valves have evolved significantly—from early cage-ball designs to modern bileaflet configurations—addressing various hemodynamic and biocompatibility challenges. This review comprehensively examines the evolution, design principles, and clinical applications of mechanical heart valves. The developmental trajectory of mechanical heart valves demonstrates remarkable engineering innovation, progressing from the pioneering Starr–Edwards caged-ball valve to sophisticated bileaflet designs such as the St. Jude Medical and ON-X valves. Material science advancements, particularly pyrolytic carbon technology, have revolutionized valve durability and thromboresistance. Clinical outcomes data demonstrate excellent long-term durability exceeding 25 years, with principal complications relating to thromboembolism and anticoagulation-related bleeding. Current research focuses on novel designs incorporating computational fluid dynamics optimization and innovative materials such as superhydrophobic surfaces and nanomaterials. Therefore, optimizing the design of valve structures may provide greater assurance of mechanical durability. However, despite some progress, the ideal mechanical valve that balances perfect hemodynamics, thromboresistance without anticoagulation, and lifelong durability, remains elusive. Continued advancement will require multidisciplinary collaboration between engineers, materials scientists, clinicians, and regulatory bodies to address remaining challenges in mechanical heart valve technology.