<p>Soft bioelectronics require metallic interfaces that mechanically conform to biological tissues while maintaining stable electrical functionality under dynamic deformation. Among metallic materials, gold (Au) has emerged as a dominant platform due to its high conductivity, chemical stability, and compatibility with ultrathin and nanostructured configurations. However, the large mechanical mismatch between stiff metals and soft substrates leads to strain transfer into the metallic layer, resulting in strain localization, crack formation, and eventual electrical failure. These limitations cannot be fully resolved by material property optimization alone, as the mechanical stability of metallic interfaces is fundamentally governed by how externally applied deformation is transferred and subsequently redistributed within the structure. From this perspective, mechanically compliant metallic interfaces must be engineered to regulate strain transfer and control strain localization through structural design. In this review, we establish a unified design framework for engineering mechanically compliant metallic interfaces by linking strain transfer, strain localization, and strain redistribution across different structural strategies. Representative approaches include geometric architectures that decouple deformation through structural transformation, percolation networks that redistribute strain via dynamic reconfiguration of conductive pathways, crack-engineered metallic films that accommodate deformation through controlled crack evolution, and interfacial engineering that modulates strain transfer at the metal–substrate interface. We further discuss how these strategies enable robust electrical performance under mechanical deformation and highlight emerging applications in wearable and implantable bioelectronic systems. Finally, we outline future opportunities for nanostructured Au-based interfaces as a pathway toward mechanically stable and functionally integrated soft bioelectronic platforms.</p>