Acrylamide (AA) is a toxic and potentially carcinogenic compound formed in carbohydrate-rich foods subjected to high-temperature processes such as frying, baking, and roasting. Its adverse health effects, including neurotoxicity and carcinogenicity, have raised serious concerns regarding food safety. In this study, we developed a novel fluorescent sensor based on a manganese metal–organic framework (Mn-MOF) incorporating 2-(2-hydroxyphenyl)benzothiazole (HBT) for the rapid and sensitive detection of AA in food and water samples. The Schiff base 3-((3-(benzo[ d ]thiazol-2yl)-5-bromo-2-hydroxybenzylidene)amino)-5-(1-hydroxyvinyl)benzoicacid (HBTN) precursor was synthesized via a condensation reaction and subsequently used to fabricate Mn-MOF-HBT through a solvothermal method. The structure of the Mn-MOF-HBT fluorescent probe was characterized by FTIR, SEM, EDS/X, and TGA analyses. The sensor exhibited a fluorescence “turn-off” response upon exposure to AA, with a low detection limit of 1.08 × 10−9 M and a rapid response time of 10 s in Britton–Robinson buffer (0.04 M, pH 8.0) at λem = 468 nm. Selectivity studies confirmed negligible interference from various metal ions, drug molecules, and biological substances. The method was further validated using real samples, including water and fried potato extracts, showing satisfactory recovery and %RSD values. Owing to its high sensitivity, rapid response, and operational simplicity, the Mn-MOF-HBT probe demonstrates strong potential for routine monitoring of acrylamide in complex food and environmental matrices, contributing to enhanced public health surveillance and risk assessment.