Copper (Cu) has high electrical conductivity and is widely used for many industrial applications. However, pure Cu is very soft and improving the mechanical properties of Cu comes at the great expense of electrical and thermal conductivity. In this work, high-performance Cu with superior mechanical properties and reasonable electrical/thermal conductivity was fabricated using a scalable two-step method. First, Cu micro-powders with uniformly dispersed tungsten carbide (WC) nanoparticles were created by a molten salt-assisted self-incorporation process. A bulk nanocomposite was then obtained by melting the powders under pressure. The as-solidified Cu with 40vol% uniformly dispersed WC nanoparticles exhibits high hardness, a yield strength over 1000MPa, a Young's modulus of over 250GPa, and reasonable electrical and thermal conductivity.