Robust　amorphous　glass　protected　CsPbBr3　(CsPbBr3@glass)　perovskite　quantum　dots　(PeQDs)　with　ultra-pure　green　emission　and　superior　long-term　stability　are　highly　desirable　for　developing　wide-color-gamut　liquid　crystal　displays.　However,　most　of　the　reported　CsPbBr3@glass　nanocomposites　are　subject　to　low　external　quantum　efficiency　(EQE).　This　work　demonstrates　that　ZrO2　additive　has　an　＇accumulation＇　effect　on　the　borosilicate　glass　network　structure　to　promote　in　situ　nucleation/growth　of　PeQDs　inside　glass　rather　than　self-crystallization.　This　effect　is　beneficial　in　reducing　surface　defects,　improving　the　quality　of　PeQDs,　and　thus　boosting　radiative　recombination　of　excitons.　As　a　consequence,　the　as-prepared　CsPbBr3@glass　shows　a　record　EQE　of　up　to　75%　and　can　pass　the　accelerated　aging　tests　at　85　°C/85%　RH　for　1000 h　and　blue　light　irradiation　over　2000 h.　Finally,　a　prototype　display　using　CsPbBr3@glass-based　straight-down　backlit　unit　is　designed　and　gains　more　favorable　responses　in　blind　selection　tests　for　its　high　brightness　of　2647 cd m−2　and　high　color　purity　of　88%.　The　findings　will　pave　the　way　for　realizing　the　commercial　application　of　CsPbBr3@glass　nanocomposite　in　PeQDs-converted　backlit　display.　©　2023　Wiley-VCH　GmbH.