The present study details the changes in photoluminescence properties stimulated by the structural changes in consequence of doping the II–VI nanocomposite thin‐film semiconductor cadmium sulfide (CdS) with the IB metallic ion Ag+. The synthesis of the matrix and doped semiconductors was performed using low‐temperature chemical bath deposition (CBD). The doping percentage of the CdS matrix was determined by energy‐dispersive X‐ray spectroscopy (EDS) with a value around 3%. The crystallographic study shows a cubic (1 1 1) preferential growth plane for the undoped material. Both X‐ray and HRTEM characterizations show the presence of a polycrystalline structure for the Ag+‐doped sample. Measurements of particle size from HRTEM micrographs confirm quantum confinement with a reduction of the average particle size from 5.46 to 4.12 nm in the doped sample. The photoluminescence study shows intense downshifted emissions in the green range of the visible spectrum. This could be due to the shallow electron traps formed by crystalline defects in the lattice, which are induced by the metallic ion. This study also shows higher‐energy emissions due to the decrease of the particle size below the effective CdS exciton Bohr radius. Ag+ doping induces novel optical effects on the nanostructured semiconductor cadmium sulfide (CdS). The nanocomposite was obtained by chemical bath deposition (CBD). This technique allows in‐synthesis doping which promotes structural modifications stimulating luminescent emissions not possible in the undoped material.