Composite nickel coatings obtained via the electrodeposition technique play a major role in various engineering fields ranging from automotive to aerospace. Ongoing research is focusing on enhancing its mechanical properties by embedding in the nickel matrix various strengthening particles in either the nano or the micro scale [1,2]. Nitrogen-doped carbon dots (NCDs) belong to the novel and rapidly advancing subcategory scientific area of carbonaceous nanomaterials, which exhibit improved properties, while they can be produced by green chemistry methods and can be exploited in various fields such as energy, environment or catalysis [3]. Interestingly, only few studies refer to composite nickel-matrix/NCDs and the resulting mechanical properties [4]. In the current study we report the successful incorporation of NCDs, fabricated by hydrothermal treatment and microwave irradiation, in a nickel-matrix coating through a one-step electrodeposition process at the direct current regime. Quantitative stoichiometric analysis of the carbon content in the coatings was achieved by means of an infrared combustion analyzer. In addition, the coatings were studied for their microstructural characteristics and surface morphologies, by means of X-ray diffraction and scanning electron microscopy, respectively. The mechanical properties of the coatings were studied by performing microhardness indentation testing. This study will also permit us to discuss a new additive-free composite nickel coating with enhanced hardness properties to be exploited for potential mechanical applications.