Despite turning could be replaced by grinding as a finishing machining process, it is considered not satisfactory for elongating the fatigue life of the component because of the produced tensile residual stresses and irregularities formed at the surface. Therefore, a complimentary operation should be applied after hard turning. Slide diamond burnishing process is a mechanical finishing operation used after hard turning to further decrease the surface roughness, introducing compressive residual stresses, increasing the microhardness, and refining the microstructure of the surface and subsurface layer of the workpiece. The main result is increasing the fatigue life of the rotating components subjected to cyclic loading. In this work, the simultaneous effect of changing the burnishing speed, feed, and force of slide diamond burnishing on surface roughness, residual stresses, and microhardness of 42CrMo4 hard-turned steel was studied. It was found that the effect of one parameter was highly affected by the others. As a result, the optimal burnishing parameters were specified, with which better surface quality was obtained than after grinding.