This paper studies the structure, elemental composition, and microhardness of plasma faced highspeed molybdenum steel layer formed on medium-carbon steel base plate in a nitrogen environment. The study is conducted using modern physical materials science methods. The formed polycrystalline dendritic type structure is revealed to be containing localized chemical elements, such as Mo, Cr, Al, Si, O2, and N2. The point-by-point X-ray microanalysis shows that hard-faced layer areas enriched with Al atoms contain carbon, oxygen, and nitrogen atoms, as well. It is demonstrated that Al forms submicron-sized oxycarbonitrides randomly located in the structure. Also, it is revealed that the microhardness of the hard-faced layer depends significantly on the distance to the steel base plate. The 1 mm thick hard-faced layer has the highest microhardness of 5.60 GPa, which is almost 1.8 times higher than the microhardness of the steel base plate. The microhardness of the hard-faced layer decreases monotonically when the distance from the steel base plate increases until almost reaching the microhardness of the latter.