Abstract: High-performance alloys are indispensable in modern engineering because of their exceptional strength, ductility, corrosion resistance, fatigue resistance, and thermal stability, which are all significantly influenced by the alloy interface structures. Despite substantial efforts, a comprehensive overview of interface engineering of high-performance alloys has not been presented so far. In this study, the interfaces in high-performance alloys, particularly grain and phase boundaries, were systematically examined, with emphasis on their crystallographic characteristics and chemical element segregations. The effects of the interfaces on the electrical conductivity, mechanical strength, toughness, hydrogen embrittlement resistance, and thermal stability of the alloys were elucidated. Moreover, correlations among various types of interfaces and advanced experimental and computational techniques were examined using big data analytics, enabling robust design strategies. Challenges currently faced in the field of interface engineering and emerging opportunities in the field are also discussed. The study results would guide the development of next-generation high-performance alloys.