Single-phased and white-emissive quantum dots (QDs) with a broadband spectrum are highly desirable as color converter for white light-emitting diodes (WLEDs) and have been less researched up till now. In this work, a series of copper gallium selenium based multicomponent QDs including quaternary Cu-Zn-Ga-Se (CZGSe) and quinary Cu-Mn-Zn-Ga-Se (CMZGSe) QDs were synthesized. From the perspective of thermodynamics and kinetics, the comparison between PL spectra under increasing temperatures via one-pot and hot-injection methods indicated that the formation of CZGSe cores originated from the diffusion of Cu into Zn-Ga-Se nanoparticles. For wider spectra distribution, the incorporation of Mn gave rise to Mn d-d emission around 590 nm. Together with Cu-related emission about 500 nm and intrinsic emission around 430 nm, white emission of CMZGSe QDs could be realized well-tuned by incremental ZnSe deposition, whose chromaticity coordinates shifted along with the Planckian locus. These results about multicomponent alloyed QDs enrich mechanistic insight for the formation kinetics and reveal the potential to fabricate better color rendering WLEDs.