Near-infrared (NIR) phosphor-converted light-emitting diode (pc-LED) has emerged as the most promising NIR light source, highlighting the importance of exploring phosphors with excellent efficiency and sufficient spectral coverage. Herein, a garnet Na2CaHf2Ge3O12:Cr3+ phosphor with an internal quantum efficiency (IQE) of 79.2% has been developed, which exhibits a relatively long wavelength NIR emission peak at 830 nm and a full width at half maximum (FWHM) of 144 nm. Moreover, the emission peak can be gradually tuned to 903 nm with an emission intensity maintaining over 60% utilizing a chemical unit co-substitution strategy. Thus, the developed material in this work has an excellent efficiency with a relatively long wavelength NIR emission and wide-range spectral tunability, being promising for multifunctional spectroscopy applications.