This paper reports on the effect of a sulfurization thermal process of the silicon carbide surface on the properties of Ni/4H-SiC Schottky barrier. In particular, the incorporation of sulfur (S) in the 4H-SiC near-surface region was observed at the process performed at 800 °C, without any significant effect on the surface morphology. On the other hand, Ni/4H-SiC Schottky contacts fabricated on the sulfurized 4H-SiC surface showed a 0.3 eV reduction of the average barrier height with a narrower distribution, with respect to the untreated sample. These results were explained by an increase of the 4H-SiC electron affinity after sulfurization, and a Fermi level pinning effect.