Purpose <p>Cadmium (Cd) toxicity poses a significant risk to environmental health and agricultural productivity, imposing sustainable and eco-friendly management strategies. In this study, a modified biochar coupled with a microbial strain of <i>Trichoderma</i> fungus was evaluated for Cd remediation in tomato plants.</p> Methods <p>A silica-embedded biochar with improved adsorption properties and porosity was synthesized and characterized using microscopic and spectroscopic methods. The biochar was coupled with a Cd-tolerant strain of <i>Trichoderma viridescens</i>, exhibiting high biosorption and Cd removal efficiency, to investigate their synergistic effects on soil Cd dynamics, metabolic responses, and growth in tomato plants under Cd stress.</p> Results <p>When applied with <i>T. viridescens</i>, the biochar exhibited a synergistic effect, outperforming their individual treatments, which was evident in decreased metal bioavailability and mobility through transformed Cd speciation in the soil. The soil amendments significantly reduced Cd accumulation in plant parts, enhanced nutrient uptake, and improved plant metabolic profiles. Plants showed 11 defined metabolites 6 amino acids, 1 sugar, 2 organic acids, and Choline) whose accumulation was increased in treated plants. Genes related to the key metabolic pathways, including ascorbic acid biosynthesis, were upregulated, along with improved photosynthetic pigments and antioxidant enzyme activities. These biochemical, physiological, and metabolomics improvements increased plant tolerance to Cd stress, enhancing plant growth attributes.</p> Conclusion <p>This study underscore the importance of integrating advanced materials, such as silica-modified biochar, with bioagents for Cd remediation and offers an eco-friendly, cost-effective strategy to alleviate heavy metal toxicity and disclose possible molecular targets for improving plant resilience.</p>