<p>Vitrification-devitrification process often results in the formation of translucent/transparent bulk glass-ceramics/ceramics with functionalities comparable to their crystalline counterparts. Here we show a significant enhancement and tunability of luminescence in Mg₂Al₄Si₅O_{18+1.5<i>x</i>}:<i>x</i>Eu²⁺ (MAS:<i>x</i>Eu) powders after being subjected to a vitrification-devitrification protocol. In MAS:<i>x</i>Eu powders, Eu²⁺ occupies multiple-sites in MAS hollow channels, demonstrating tunable blue-to-yellow emissions with red-afterglow. After vitrifying-devitrifying MAS:<i>x</i>Eu powders, the derived ceramics showcase red-emissions with a near-unity luminescence efficiency, higher-thermal stability, and longer-persistent luminescence, enabling the fabrication of red-emitting lighting device with an ultrahigh brightness. The luminescence enhancement is ascribed to the increase of oxygen-related defects in the network during vitrification process that facilitates an efficient trapping-detrapping process. From structural analyses, the luminescence tunability can be attributed to the change in the heterogeneous structure of the channel wall, amending the distribution of Eu²⁺ multiple-sites. Thus, our approach has opened a new avenue for advancing the design of high-performance luminescent materials.</p>