A bacterial and viral infection causes life threatening diseases owing to the abuse of antibiotics and the development of antibiotic resistance microbes. Currently, biopolymers have been considered as the most promising materials in the medical field. Herein, the biogenic chitosan-functionalized MoS 2 nanocomposite was prepared by the hydrothermal method with the liquid exfoliation process. The X-ray diffraction (XRD) results of chitosan–MoS 2 hybrid nanocomposite revealed that MoS 2 nanoparticle was found to be 42 nm with a hexagonal crystal structure. FTIR and Raman spectrum revealed that the nitrogen functionalities in the chitosan interacted with MoS 2 to form the nanocomposite. The XPS spectrum of chitosan–MoS 2 nanocomposite confirms that C, N, O, Mo, and S exist in the nanocomposite. Thermal gravimetric analysis (TGA) and Differential thermal analysis (DTA) analysis showed that the chitosan–MoS 2 nanocomposite has higher thermal stability up to 600 °C. In the antibacterial application the chitosan–MoS 2 hybrid nanocomposite shows zones of inhibition against S. aureus as 22, 28, and 32 mm, and against E. coli as 26, 30, and 35 mm. In the anticancer analysis, chitosan–MoS 2 hybrid nanocomposites showed a maximum cell inhibition of 65.45% at 100 μg/mL−1, resulting in the most significant MCF-7 cell inhibition. • The chitosan-MoS 2 was synthesized by hydrothermal with liquid exfoliation process. • XPS spectrum proves chitosan was functionalized with MoS 2 via π-π interaction. • TEM with SAED pattern confirms MoS 2 was formed with a multilayered 2D structure. • TGA curve shows adding MoS 2 improve the thermal stability of composite up to 650 °C. • It successfully inhibits S. aureus , E.coli bacteria and MCF-7 breast cancer cells. [ABSTRACT FROM AUTHOR]