A deep-red-emitting Na1.57Zn0.57Al10.43O17:Mn4+ (NZAO:Mn4+) phosphor has been synthesized by high-temperature solid-state reaction method in air. X-ray diffraction patterns confirmed only one pure phase (NZAO) in the NZAO:Mn4+ phosphor. The excitation spectrum of NZAO:Mn4+ phosphor monitored at 695 nm covered the region from 220 nm to 600 nm. Under excitation at 300 nm, NZAO:Mn4+ phosphor showed deep-red emission due to the 2E → 4A2 transition of Mn4+ ion with the lattice vibrations. In NZAO:Mn4+ phosphor, the optimal Mn4+ content is 1.0%. The lifetime of NZAO:1%Mn4+ phosphor is 0.47 ms. The effect of the crystal field on the luminescence properties of Mn4+ ion and the luminous mechanism are explained based on the Tanabe-Sugano diagram of Mn4+ ion in an octahedral symmetry environment. These experimental results will be helpful for research into the basis of the luminescence properties of other Mn4+-doped materials.