This study presents bacterial reduction by visible light-absorbing nanocomposite nitride and oxynitride films showing absorption in the visible spectral range and their silver (Ag) derivatives. The design, sputtering, bacterial evaluation, and surface characterization of uniform and adhesive nanoparticulate nitride and oxynitride films are described in detail. Bacterial reduction was observed by these Ag-nitrides/oxynitrides to proceed in the dark and with higher kinetics under daylight/actinic light irradiation. The special interest regarding the nitrides is their low cytotoxicity and chemical stability, which make them especially suited as supports for highly oxidative Ag nanoparticles. The Ag-TiON fast inactivation kinetics concomitant with low cytotoxicity is the essential requirement for the potential practical application of these antibacterial surfaces. The aims of this study are to show the increased kinetics of bacterial activation as a function of nitride/oxynitride composition, to report their operational long-term stability, and to characterize the film composite microstructure.