Tunable electronic properties in transition metal dichalcogenides (TMDs) are essential to further their use in device applications. Here, we present a comprehensive scanning tunneling microscopy and spectroscopy study of a doping-induced charge density wave (CDW) in semiconducting bulk 1T-ZrSe₂. We find that atomic impurities that locally shift the Fermi level (E_F) into the conduction band trigger a CDW reconstruction concomitantly to the opening of a gap at E_F. Our findings shed new light on earlier photoemission spectroscopy and theoretical studies of bulk 1T-ZrSe₂ and provide local insight into the electron-doping-mediated CDW transition observed in semiconducting TMDs.