Ca₈MgLu(PO₄)₇:Ce³⁺,Tb³⁺,Mn²⁺ (abbreviated as CMLP:Ce³⁺,Tb³⁺,Mn²⁺) phosphors were synthesized by a high-temperature solid-state method. X-ray diffraction (XRD), photoluminescence (PL) spectra, GSAS structural refinement, and absolute quantum yield and lifetimes were used to characterize the samples. Increasing the Ce³⁺ doping concentration in the CMLP host shifts the emission peak from 360 to 374 nm. Under UV excitation, the energy transfers (ETs) from Ce³⁺ to Tb³⁺ and from Ce³⁺ to Mn²⁺ in the CMLP host occurred mainly via a dipole–quadrupole mechanism, and the critical distances of the ion pairs (R_C) were calculated by the quenching concentration method and spectral overlap method, respectively. The emission colors of the CMLP:Ce³⁺,Tb³⁺,Mn²⁺ samples could be adjusted from blue to green, and eventually to orange–red by the ET between Ce³⁺ and Tb³⁺/Mn²⁺. Moreover, a white light emission tunable over a wide range was obtained by precisely controlling the contents of Ce³⁺, Tb³⁺ and Mn²⁺. Temperature dependent luminescence spectra proved the good thermal stability of the as-prepared phosphor. Based on the good PL properties and varied hues of the CMLP host achieved by adjusting the doping concentration of the activators (Ce³⁺, Tb³⁺, Mn²⁺), CMLP might be promising as a host material for solid-state lighting and display fields.