<p>Enhancing the electrical conductivity of copper (Cu), the most widely used electrical conductor, is crucial for advancing energy-efficient technologies and industrial innovation. The integration of graphene (Gr), a two-dimensional material with exceptional carrier mobility, into Cu has emerged as a promising route to next-generation composite conductors. However, the practical realization of high-performance Cu-Gr composites (CGC) is hindered by critical challenges, including weak interfacial bonding, nonuniform Gr dispersion, and processing-induced structural defects, which can limit conductivity gains. A detailed understanding of the interfacial interaction mechanisms between Cu and Gr, coupled with the optimization of processing methodologies, is essential to overcome these barriers. In this review, we examine the intrinsic physical properties of Cu and Gr, clarify their interfacial interaction mechanisms, summarize design strategies and processing techniques for improving CGC conductors, and evaluate the electrical performance of state-of-the-art CGC. We further identify current knowledge gaps and outline future research directions, including advanced interfacial engineering, scalable fabrication, and predictive modeling for optimizing CGC properties.</p> Graphical abstract <p></p>