Towards the development of sustainable and multifunctional materials, a hybrid polymer composite system composed of cellulose fiber, sodium alginate and titanium oxide (TiO₂) nanoparticles has been made in the form of beads. The cellulose fiber was extracted from Areca husk, an agricultural waste material. TiO₂ was made in nanosize by the green synthesis method using Azadirachta indica (neem) leaf extract. Hydrogel beads were fabricated from a mixture of sodium alginate, cellulose fiber, and TiO₂ nanoparticles by an ionic gelation process achieved using calcium chloride. The physicochemical characterization of the gel beads was carried out using FTIR, SEM, XRD, TGA, and TEM techniques. The pH-responsive swelling of the gel beads was demonstrated from the swelling studies carried out in aqueous medium under different pH conditions. The beads were evaluated for the slow release of bioactive agents, namely neem seed oil (NSO), a biopesticide and urea, and a fertilizer molecule. The loading and release of these agents were studied in an aqueous medium. The results indicated percentage loadings of 93.96% and 90.55% for neem seed oil and urea, respectively. The slow release of NSO and urea was observed to occur from the gel beads in a sustained manner during a 3-day period. The kinetic analysis of the release data indicated the release of both agents, following the Korsmeyer–Peppas model. The release exponent ‘n’ obtained from this model was less than 0.5 in both cases, indicating the release to be a Fickian process. The NSO- and urea-loaded gel beads were also evaluated for antibacterial characteristics against E. coli and S. aureus, and the results indicated the role of NSO in enhancing the antibacterial activity of the gel. Thus, this study exemplifies a sustainable approach to valorize agricultural waste for the development of smart materials in agricultural use.