The toxicity of Pb and the instability of lead halide perovskites are the main obstacles to the practical application of lead-based nanocrystals (NCs). In this paper, all-inorganic Zn2+-doped lead-free perovskite (CsMn1–x Zn x Cl3) NCs were synthesized by a hot-injection method. Mn2+ ions were partially replaced by Zn2+ ions, and the energy transfer between Mn2+ was effectively suppressed. Because of this, excitons are more advantageously confined to the [MnCl6]4– octahedron. Target CsMn0.95Zn0.05Cl3 NCs were endowed with red emission at 654 nm with CIE coordinates of (0.70, 0.30) closing to the standard value of NTSC, and their photoluminescence quantum yield was increased to 77.1%, which is higher than those of Mn-based lead-free perovskites previously reported. Finally, a white light-emitting diode (LED) with adjustable emission from warm to cold white was realized by mixing Cs3MnBr5, CsMn0.95Zn0.05Cl3, and a blue phosphor on a 382 nm ultraviolet LED chip.