A novel carbon-based nc-CrC/a-C(Al) nanocomposite coating was fabricated by combination of metallic Cr and Al doping via a multifunctional magnetron sputtering system. The composition and structure of the as-fabricated coating were investigated by X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). This confirmed that the typical nanocrystallite/amorphous microstructure architecture can be achieved by codoping Cr and Al in the amorphous carbon matrix. A nano-indenter, interferometer, and ball-on-disc tribometer were used to test the hardness, internal stress, and tribological properties. The results show that the carbon-based nc-CrC/a-C(Al) nanocomposite coating possesses superior mechanical properties with low internal stress and relatively high hardness as well as strong adhesion strength. Remarkably, the as-fabricated carbon-based coating can achieve low friction and antiwear performance with a friction coefficient of 0.05 and wear rate of 2.0 × 10⁻¹⁶ m³/N·m under ambient air. This indicates that the carbon-based nc-CrC/a-C(Al) nanocomposite coating has great potential in engineering applications.