Trivalent arsenic (AsIII) is the most toxic form of arsenic, accumulates in plant systems through aquaporins, and inhibiting plant growth. This study focuses on mitigating the bioavailability of arsenite (AsIII) in agricultural soils through biological approaches. A potential AsIII tolerant bacterium Pseudomonas aeruginosa VS3 was isolated from contaminated soil. Subsequent analysis revealed that this strain can produce exopolysaccharides (EPS) and biofilms. Additionally, the strain exhibited production of plant growth promoting traits, incuding Indole-3-acetic acid (IAA), gibberellins, and silicon (Si) solubilisation. Biotransformation assay demonstrated that strain can oxidize AsIII to the less toxic arsenate (AsV) with conversion efficiency of 51%. Findings from the field trial proven that P. aeruginosa significantly reduced AsIII toxicity in Solanum lycopersicum and boosted plant growth under AsIII stress conditions. Additionally, inoculation with P. aeruginosa enhanced the activities of antioxidant enzymes (40% increase in peroxidase and a 17% increase in phenylalanine ammonia-lyase) compared to untreated controls under AsIII stress. The bacterial treatment reduced arsenic accumulation in root tissues, demonstrating P. aeruginosa VS3's potential as a bioremediation agent to alleviate arsenite stress and enhance plant growth.