The development of a new class of alternative plastics has been encouraged in the past few years due to the serious environmental issues, such as toxicity and carbon dioxide emissions. Hence, the introduction of renewable, biodegradable, and biocompatible materials is becoming critical as substituents of conventional synthetic plastics. To design a new system of novel TEMPO-oxidized cellulose nanofibrils (TOCNs)/graphene oxide (GO) composite, the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was utilized to disintegrate never-dried wood nanofibrillated cellulose (NFC). GO was incorporated through high intensity homogenization and ultrasonication with varying degree of oxidation (0.5X, 1X, and 2X) of NFC and GO percent loadings: 0.4, 1.2, and 2.0wt %. As a result, despite the presence of carboxylate groups and graphene oxide (GO), X-ray diffraction (XRD) test showed the crystallinity of the bio-nanocomposite was not altered. Scanning electron microscopy (SEM) was used to characterize their morphologies. In addition, the thermal stability of TOCN/GO composite decreased upon oxidation level, and dynamic mechanical analysis (DMA) signified strong intermolecular interactions with the improvement in Young's storage modulus, and tensile strength. Fourier transform infrared spectroscopy (FTIR) was employed to see the hydrogen bonds between GO and cellulosic polymer matrix. The oxygen transmission rate (OTR) of TOCN/GO composite decreased. The water vapor permeability (WVP) was not significantly affected by the reinforcement with GO, but the moderate oxidation enhanced the barrier properties. Ultimately, the newly fabricated TOCN/GO composite can be utilized in a wide range of life science applications, such as food and medical industries.