In this study, pullulan (PULL) nanocomposite films containing tempo cellulose nanofibrils (TOCNs) and Ag nanoparticles were successfully prepared using a solution casting technique in aqueous solutions. X-ray diffraction results and optical microscopy images revealed the coexistence of Ag and PULL/TOCNs blend matrix as well as the uniform distribution of Ag nanoparticles. The Fourier-transform infrared data showed that a good interaction occurred between TOCNs, Ag, and PULL matrix; the prepared composite film showed improved characteristics including higher tensile strength, thermal stability, water barrier properties and reduced moisture susceptibility compared to a neat PULL film. In addition, the prepared film is biodegradable and possesses antimicrobial characteristics. These excellent properties clearly indicate that this type of ternary nanocomposite film may have prospective food packaging and medical application.