The escalating contamination of heavy metals (HMs) in agricultural systems poses a significant threat to food security and human health. This chapter will explore the potential of biochar derived from bio-genic, agricultural, and urban waste as a sustainable solution for mitigating HM uptake in crops. By examining the pyrolysis process and the unique properties of biochar produced from diverse feedstocks—such as crop residues, animal manure, municipal solid waste, and algal biomass—the chapter will highlight how feedstock composition influences biochar’s ability to immobilize HMs in soil. This will also compare the effectiveness of agro-based biochar (derived from rural biomass) and urban biochar (from municipal/industrial waste) in mitigating HM contamination in soil-crop systems, emphasizing their adsorption capacities and interactions with diverse HMs (e.g., cadmium–Cd, lead–Pb, arsenic–As, chromium–Cr, etc.). Key mechanisms, including electrostatic attraction, ion exchange, and surface complexation, coprecipitation process will be discussed to elucidate biochar’s role in immobilizing HM bioavailability. Empirical data from low-, middle-, and high-income countries demonstrate the practical application of biochar in diverse agricultural settings, emphasizing its cost-effectiveness and scalability. The chapter will also address challenges related to feedstock variability, production scalability, long-term field efficacy and the impact of soil physicochemical properties on biochar performance and its long-term implications for crop productivity and metal uptake. By integrating scientific insights into real-world applications, this work hopes to underscore the potential of biochar as a transformative tool for sustainable agriculture, offering a pathway to safer food production and improved environmental resilience.