The toxicity of heavy-metal Pb and instability of lead-based halide perovskite nanomaterials are main factors to impede their practical applications in the fields of solar cells, LEDs and scintillators. In this paper, all inorganic lead-free cesium manganese halide nanocrystals are synthesized in glass for the first time. Red photoluminescence with broad PL band, negligible self-absorption and a high photoluminescence quantum yield of 41.8% is obtained. In addition, modulating halide component can change the Mn 2+ ions coordination environment to obtain tunable photoluminescence from red to green. More importantly, cesium manganese halide nanocrystals embedded glasses exhibit outstanding long-term stabilities. Theses cesium manganese halide nanocrystals embedded glasses are also highly stable against high energy irradiation and exhibit highly efficient radioluminescence, making them promising for high-resolution X-ray imaging. These results demonstrate that cesium manganese halide nanocrystals embedded glasses are promising eco-friendly candidates for applications in light-emitting diodes and scintillators.