Developing mixed‐anion semiconductors for solar fuel production has inspired extensive interest, but the nitrohalide‐based photocatalyst is still in shortage. Here we report a layered nitro‐halide β‐ZrNBr with a narrow band gap of ca. 2.3 eV and low defect density to exhibit multifunctionalities for photocatalytic water reduction, water oxidation and CO2 reduction under visible‐light irradiation. As confirmed by the results of electron paramagnetic resonance (EPR) and density functional theory (DFT) calculations, the formation of anion vacancies in the nitro‐halide photocatalyst was inhibited due to its relatively high formation energy. Furthermore, performance of β‐ZrNBr can be effectively promoted by a simple exfoliation into nanosheets to shorten the carrier transfer distance as well as to promote charge separation. Our work extends the territory of functional photocatalysts into the nitro‐halide, which opens a new avenue for fabricating efficient artificial photosynthesis.