The CoCrFeMnNi high-entropy alloy (HEA) is distinguished by its superior mechanical properties, machinability and corrosion resistance. However, its relatively low yield strength and inadequate wear resistance constrain its applicability in structural and tribological applications. To address these limitations, this study systematically investigates the incorporation of 5vol.% silicon carbide (SiC) nanoparticles into HEA via a selective laser melting (SLM) process, with the objective of enhancing its microstructural characteristics, mechanical properties and tribological performance. Microstructural analysis reveals that the homogeneous dispersion of SiC nanoparticles (35–50 nm) within both grain interiors and boundaries promotes significant grain refinement, leading to notable improvements in compressive yield strength (55.2%), nanohardness (72.8%) and elastic modulus (20.3%) relative to the plain HEA. Tribological assessment demonstrates a substantial reduction in wear rate, with abrasive wear mechanisms prevailing at low loads. Under elevated loads, the unreinforced HEA undergoes pronounced plastic deformation and oxidation-induced degradation due to frictional heating, whereas the incorporation of SiC nanoparticles mitigates oxidation and induces a self-lubricating effect, thereby enhancing wear resistance. Worn subsurface characterization shows the formation of shear bands, high-density dislocation structures and localized nanohardness increases, elucidating the underlying deformation and wear mechanisms governing the enhanced tribological performance of the nanocomposite. These findings underscore the synergistic role of SiC nanoparticles in refining microstructure, strengthening mechanical properties and improving tribological behavior.