Linen fibres were coated with a glow‐in‐the‐dark photoluminescence, flame‐retarding, and hydrophobic smart nanocomposite using the pad‐dry‐curing process. Ecologically friendly ammonium polyphosphate and lanthanide‐activated strontium aluminium oxide (LSAO) nanoparticles were immobilized into linen fabric using eco‐friendly room‐temperature‐vulcanizing silicone rubber. Different analytical techniques were used to examine the morphological characteristics and elemental compositions of LSAO nanoparticles and treated linen textiles. The self‐extinguishing properties of the treated linen textiles were tested for their fire resistance. After 24 washing cycles, the coated linen samples retained their flame‐retarding properties. The treated linen's superhydrophobicity rose in direct proportion to the LSAO concentration. After being excited at 365 nm, the colourless luminescent film that was coated on linen surface gave out an emission wavelength of 519 nm. The photoluminescent linen was monitored to create a range of different colours, including off‐white in daytime light and green under ultraviolet (UV) light radiation, according to the Commission Internationale de l'éclairage laboratory colorimetric coordinates and photoluminescence spectra. Emission, excitation, and lifetime spectral analysis of the treated linen revealed persistent phosphorescence. For mechanical and comfort evaluation, the coated linen textiles' bending length and air permeability were assessed. Good UV light shielding and enhanced antibacterial activity were detected in the treated linens.