In this work, salicylic acid based hyperbranched polyester (HBPE) was synthesized by simple condensation method. The transformation from aliphatic nature to aromatic nature of polymer in the subsequent reaction steps were identified using FTIR and NMR results. The predictable structure and the molecular weight of the polymer were established with the help of LC-MS analysis. The amorphous nature, lowest glass transition temperature (∼31 °C) and thermal behaviour of the polymer were traced using DSC and TGA. The polymer displayed the fluorescence maxima in the 450–525 nm range with relatively narrow peak widths indicating that they had pure and intense fluorescence. The antimicrobial activity of the salicylic acid based HBPE was evaluated against the Gram negative organisms like Escherichia coli and Salmonella paratyphi, Gram positive organisms as Bacillus subtilis and Staphylococcus aureus and fungi such as Aspergillus niger, and Candida albicans. The antimicrobial effect of polymer showed better efficiency than standard antibiotic drug such as Ciprofloxacin and Clotrimazole for both bacteria and fungi respectively except in the case of microorganisms such as Escherichia coli and Candida albicans. The minimum inhibitory concentration value of the polymer against Bacillus subtilis was tested and found to be 31.25 μg mL−1.