This study reports the development of a hierarchical Ag/Sr6Bi2O9-α-Bi2O3 (Ag/SBO-BO) ternary photocatalyst derived from a metal-organic framework (MOF) for the remediation of micropollutants and inactivation of water pathogens. The Ag/SBO-BO composite exhibits a cuboidal-rod morphology with an internal hollow structure, featuring Ag nanodots (3–5 nm) decorating the high-aspect-ratio Sr6Bi2O9 nanosheets, which are epitaxially grown over porous Bi2O3 (BO)-microcrystals. This structure provides superior optical absorption, synergistic charge channelization, and enhanced photoexcited state lifetimes. The photocatalytic activity of the Ag/SBO-BO composite is evaluated for antibiotic degradation (ciprofloxacin, k = 0.0116 min−1), heavy-metal reduction (Cr6+, k = 0.0752 min−1), and bacterial inactivation (Vibrio cholerae, 96.5% in 40 min). The biocompatible nature of the composite is confirmed through hemagglutination studies. The observed photocatalytic and photoantibacterial activity is attributed to a plasmonic hot electron-promoted S-scheme charge migration pathway, as deduced from band structure analysis and radical trapping studies.This study reports the development of a hierarchical Ag/Sr6Bi2O9-α-Bi2O3 (Ag/SBO-BO) ternary photocatalyst derived from a metal-organic framework (MOF) for the remediation of micropollutants and inactivation of water pathogens. The Ag/SBO-BO composite exhibits a cuboidal-rod morphology with an internal hollow structure, featuring Ag nanodots (3–5 nm) decorating the high-aspect-ratio Sr6Bi2O9 nanosheets, which are epitaxially grown over porous Bi2O3 (BO)-microcrystals. This structure provides superior optical absorption, synergistic charge channelization, and enhanced photoexcited state lifetimes. The photocatalytic activity of the Ag/SBO-BO composite is evaluated for antibiotic degradation (ciprofloxacin, k = 0.0116 min−1), heavy-metal reduction (Cr6+, k = 0.0752 min−1), and bacterial inactivation (Vibrio cholerae, 96.5% in 40 min). The biocompatible nature of the composite is confirmed through hemagglutination studies. The observed photocatalytic and photoantibacterial activity is attributed to a plasmonic hot electron-promoted S-scheme charge migration pathway, as deduced from band structure analysis and radical trapping studies.