Herein, a protocol strategy has been designed for the preparation of ternary silver nanoparticles-supported polyaniline multiwalled carbon nanotube (Ag NPs–PANI/MWCNT) nanocomposites with a chemical interaction for catalytic and antibacterial activity. The morphological study confirmed that Ag NPs were immobilized on the surface of PANI, and afterward, Ag NPs–PANI were mixed with the MWCNTs. The X-ray diffraction technique revealed the face-centered cubic structure of Ag NPs, and the X-ray photoelectron spectroscopy study revealed the chemical constituent and signature of π–π* and C–N interactions in the nanocomposites. The ternary Ag NPs–PANI/MWCNTs nanocomposites have the apparent rate of reaction (K_app) as 5.4 × 10^–3 s^–1, higher than binary nanocomposites for catalytic reduction of 4-nitrophenol to 4-aminophenol at room temperature. Antibacterial activity of Ag NPs–PANI/MWCNT nanocomposites is higher against pathogenic bacteria. Thereafter, because of multifold applications of ternary nanocomposites, they have a broad scope in the field of environmental and healthcare sectors.