Composite coatings consisting of a nanocrystalline Ni–W alloy matrix reinforced with ZrO2 particles (average size of 50 nm) were synthesized by electrochemical deposition assisted by an external ultrasonic field. The Ni–W/ZrO2 coatings were deposited from aqueous sulphate–citrate electrolytes containing zirconia nanopowder in suspension on steel substrates in a system with a rotating disk electrode (RDE). The influence of relevant processing parameters (i.e., concentration of zirconia powder in plating bath, current density, hydrodynamic conditions, ultrasonic field frequency) on the composite characteristics was discussed. Based on micromechanical (microhardness, Young’s modulus) and microstructural (morphology, phase composition, crystallite size) properties of the coatings, the conditions for electrodeposition of crack-free, homogeneous Ni–W/ZrO2 nanocomposites with enhanced functional properties have been developed.