The isolation of cellulose from Gracilaria sp. seaweed offers a sustainable approach for developing biodegradable and edible food packaging materials. This study aimed to isolate cellulose from Gracilaria sp. and evaluate its applicability in edible film fabrication. Cellulose was isolated through sequential washing, hydrolysis, delignification, and bleaching processes, and its lignocellulosic composition was analyzed using the Van Soest method, while chemical functional groups were identified by Fourier Transform Infrared (FTIR) spectroscopy. The results demonstrated a substantial enhancement in cellulose content accompanied by effective removal of hemicellulose and lignin, confirming the efficiency of the isolation process. Edible films were subsequently prepared using Gracilaria sp. cellulose in combination with chitosan and glycerol as a plasticizer. The developed films exhibited acceptable thickness, high water solubility, improved tensile strength with increasing glycerol concentration, and glycerol-dependent surface morphology as observed by SEM analysis. FTIR confirmed the presence of characteristic cellulose functional groups within the film matrix. In addition, the edible films demonstrated antimicrobial activity against Escherichia coli, highlighting their potential as active food packaging materials. Overall, this study confirms that cellulose derived from Gracilaria sp. is a viable and sustainable raw material for the development of functional, biodegradable, and antimicrobial edible films for food packaging applications.