This study explores the potential of stubble waste biochar as a sustainable resource for construction materials, addressing the environmental challenges posed by crop stubble burning. Converting stubble waste into biochar presents a dual opportunity to mitigate air pollution and reduce carbon emissions. This research focuses on the effect of biochar production temperature on its characteristics and cementitious properties. Biochar was produced at varying temperature ranges of 450 ℃ and 550 ℃ under constant pyrolysis conditions, with a residence time of 120 min and a heating rate of 10 ℃/min. A total of five mixes were prepared: one control mix and four biochar-modified mixes with 5% and 10% cement replacement using biochar produced at both temperatures. Comprehensive characterization reveals that higher production temperatures enhance biochar reactivity, increasing its alkalinity and functional group availability, which significantly improve its interaction with cementitious materials. Results indicate that the 550 ℃ biochar at 5% replacement achieved up to a 24.6% increase in compressive strength, a 12.3% improvement in flexural strength, and a 16.5% reduction in water absorption compared to the control mix. These findings demonstrate that biochar produced at 550 ℃ exhibits superior performance, enhancing mechanical properties and promoting better integration within the cement matrix. Additionally, the incorporation of biochar contributes to a reduction in the carbon footprint of construction materials by sequestering carbon and utilizing agricultural waste. The findings underscore the critical role of production temperature in determining biochar’s efficacy as a sustainable and performance-enhancing additive, paving the way for innovative, environmentally conscious construction practices. This work highlights the transformative potential of stubble waste biochar, offering a scalable solution to environmental challenges while advancing sustainable construction materials.