The research presented in this article concerns Zr−C coatings which were deposited on 304L steel by reactive magnetron sputtering from the Zr target in an Ar−C2H2 atmosphere at various acetylene flow rates, resulting in various atomic carbon concentrations in the coating. The article describes research covering the change in the antibacterial and anticorrosive properties of these coatings due to the change in their chemical and phase composition. The concentration of C in the coatings varied from 21 to 79 at.%. The coating morphology and the elemental distribution in individual coatings were characterized using field emission scanning electron microscopy with an energy-dispersive X-ray analytical system. X-ray diffraction and Raman spectroscopy were used to analyze their microstructure and phase composition. Parallel changes in the mechanical properties of the coatings were analyzed. Based on the obtained results, it was concluded that the wide possibility of shaping the mechanical properties of Zr−C coatings in combination with relatively good antibacterial properties after exceeding 50 at.% of carbon concentration in coatings and high protective potential of these coatings make them a good candidate for medical applications. In particular, corrosion tests showed the high anti-pitting potential of Zr−C coatings in the environment of artificial saliva.