Experimental studies of x-ray photoelectron and Co $L\ensuremath{\alpha}$ x-ray emission spectra of the ZnS:Co semiconductor were carried out. It was established that Co ions are present in isovalent ${\mathrm{Co}}^{2+}$ configuration and that the Co $3d$ impurity states are localized above the top of the valence band by $1.0\ifmmode\pm\else\textpm\fi{}0.2$ eV.
