Rational control of the luminescent properties of ligand-protected coinage metal clusters has long been pursued but remains challenging. Here we explore the crucial structural and electronic factors governing the fluorescence of a diphosphine-protected Au13(dppe)5Cl23+ cluster by time-dependent density functional theory calculations. By substituting the central Au atom with group 5 to group 11 transition metal atoms, the emission wavelength is adjustable from red to blue, accompanied by enhanced fluorescence intensity compared with the undoped cluster. The evolution of light-emitting behavior upon doping and the corresponding roles of the dopant, Au cage, ligands, and their interplay are interpreted at the electronic structure level. In particular, strong dopant–Au cage interaction associated with large electron–hole overlap on the dopant are is a key factor to endow large emission energy and intensity. These theoretical results provide vital guidance for designing atomically precise nanoclusters with visible fluorescence and high quantum yield for practical uses.