1T−TiSe2 has been intensely investigated for its intriguing charge density wave (CDW) phase, which competes with emerging superconductivity. However, the mechanism of the CDW transition has been elusive with the possibility of strong excitonic interaction. Here, we investigate, using angle-resolved photoelectron spectroscopy and density functional theory calculations, the evolution of the CDW band structure upon electron doping into the surface layer by alkali metal adsorbates.