Hybridization between low-dimensional nanostructures has received considerable research interest, owing to its usefulness in the exploration of energy-efficient functional materials. In the present study, an effective method to synthesize high-performance electrocatalysts was established by employing monolayered two-dimensional RuO2 nanosheets and Co2+ ions as conductive additives and linker species, respectively. Intimately coupled hybrid electrocatalysts of Co–MoS2–RuO2 were synthesized through the self-assembly of isocharged MoS2 nanoflowers and RuO2 nanosheets using oppositely charged Co2+ linkers. Efficient interfacial charge transfer from RuO2 nanosheets to MoS2 nanostructures can be achieved via electrostatically driven strong electronic coupling between MoS2/RuO2 nanostructures promoted by Co2+ linkers. The co-incorporation of RuO2 nanosheets and Co2+ ion linkers was found to be considerably effective for optimization of the electrocatalyst performance and electrochemical stability of MoS2 nanoflowers for the hydrogen evolution reaction in acidic and alkaline electrolytes. The beneficial roles of RuO2 nanosheets and Co2+ ions in the optimization of the electrocatalyst performance were attributable to the improvement of electrocatalysis kinetics, the expansion of the electrochemical active surface area, and the promotion of charge transport upon hybridization.