The application of environmentally friendly and sustainable catalysts requires efficient and safe preparation methods using cheap and renewable materials. Although many metal nanoparticles (NPs) have low colloidal stability, they are still very effective as catalysts. Using a straightforward method, we developed a bacterial cellulose–glycol chitosan–silver (BC–GCS–Ag) nanocomposite, by introducing both AgNPs and self-crosslinked GCS within the BC network. Self-crosslinking of GCS occurred during the formation of AgNPs by employing the glycol moieties for reduction to produce aldehyde functionalities, thereby forming Schiff's base bonds within the GCS structure. Using GCS, well-defined AgNPs within the BC matrix. The formation of AgNPs and the self-crosslinking of GCS were characterized using UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that spherical AgNPs with a mean diameter of 10 nm exhibited a well-organized structure within the BC–GCS matrix. The BC–GCS–Ag nanocomposite was applied as dip catalyst for the reduction of 4-nitrophenol (4NP) to 4-aminophenol (4AP), chosen as a model reaction. The results showed that the catalytic reaction was completed within 4 min, with high reusability (10 times) and without loss of catalyst. The reaction followed pseudo-first-order kinetics with a high rate constant of 0.582 min−1. Therefore, the BC–GCS–Ag dip catalyst is an attractive alternative for environmentally friendly and sustainable catalysis, owing to its exceptional catalytic performance, high recyclability, and stability, as well as the minimal environmental footprint of the supporting materials.