For the first time, we report in situ exfoliated titanate nanosheet-supported silver nanoparticles (AgNPs) toward environmental sustainability through rapid catalytic reduction of p-nitrophenol (4-NP), organic dyes for decoloration, as well as by inhibiting the growth of microbes. The ternary nanocomposite hydrogel has been synthesized through stabilization of an anionically charged titanate sheet by three-dimensional amino-functionalized chemically cross-linked amylopectin for proper growth and stabilization of AgNPs. Here, titanate nanosheets act as an excellent solid support for proper fabrication of AgNPs that could restrict its agglomeration and rapid leaching of AgNPs from the ternary nanocomposite hydrogel. The structural confirmation as well as the stability of titanate nanosheets along with AgNPs have been studied using various characterization techniques. The preparaed nanocomposite hydrogel demonstrates excellent catalytic efficacy and recycling ability toward rapid reduction of toxic 4-NP and decoloration of organic dyes. Notably, the complete reduction of 4-NP could be accomplished within 16 s using 5 mg of as synthesized cl-AP/exf.LT-AgNPs in the presence of excess NaBH4. The excellent catalytic efficiency of the ternary nanocomposite hydrogel arises from the synergistic effects of cross-linked amylopectin stabilized titanate nanosheets and in situ fabrication of AgNPs. Moreover, the strong bactericidal activity (3.2 mg/mL for 107 cells/mL of Escherichia coli and Bacillus subtilis) of the ternary nanocomposite hydrogel would overcome the limitations for removal of water-soluble organic pollutants and microbial contaminants owing to future perspective on environmental sustainability.