In this study, copper (Cu)/polydopamine (PDA) composite was fabricated by vacuum hot-press sintering of micrometer-sized Cu particles covered with PDA film tailored at the nanometer scale thickness. The resultant compacts exhibited much higher electrical conductivity than the uncoated counterparts. Analyses of sintered samples using scanning and transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy revealed the conversion of PDA into carbonized PDA (cPDA). The increased mass density and grain growth are likely responsible for improved electrical conductivity of the composite material.