The growing demand for broadband near-infrared (NIR) irradiation in security, biomedicine, and food science is driving the development of new NIR light sources. Herein, a series of Cr³⁺/Ni²⁺ co-doped transparent glass ceramics containing octahedrally coordinated KCdF₃ nanocrystals have been successfully prepared. Under 450 nm blue light excitation, the combination of Cr³⁺ and Ni²⁺ results in an ultra-broadband NIR emission band ranging from 700 to 1800 nm. Based on the excitation and emission spectra and the decay lifetime curves, the energy transfer (ET) efficiency from Cr³⁺ to Ni²⁺ is confirmed to be 50.2%. A glass ceramic-converted NIR-LED was fabricated by integrating a commercial blue LED chip with a representative Cr³⁺/Ni²⁺ co-doped glass ceramic, and have been demonstrated potential applications in the areas of covert information recognition and night vision illumination. Our investigation provides new insights into the development of ultra-broadband NIR light sources that are both cost-effective and efficient.