<p>Waste foundry sand (WFS) is a by-product of foundry industries and is often disposed of in landfills. It is produced at a rate of around 0.6 tons per ton of foundry production. Conventional clay brick manufacturing is highly energy-intensive, primarily because of the high-temperature kiln firing process, which results in substantial fossil fuel consumption and associated greenhouse gas emissions. This work describes the development of one-part alkali-activated bricks utilizing WFS to provide a sustainable solid waste management solution and lower the embodied energy of bricks. Fly ash (FA) and blast furnace slag fine powder were found to be regionally accessible materials for experiments, along with anhydrous sodium metasilicate (ASS) as the activator. WFS was utilized as a full replacement for natural sand, serving as a sustainable alternative in the granular matrix of the alkali-activated binder system. To create alkali-activated WFS bricks (AFSB), FA and BFSFP were combined in varying amounts with ASS (8% and 10% of the binder). The binder-WFS proportions were 1:1, 1:2, and 1:3, whereas the water-to-binder ratio was adjusted to maintain constant consistency. AFSB were divided into three classes according to their compressive strength (which ranged from 4 to 18&#xa0;MPa) following an evaluation of their various physico-mechanical characteristics, following IS 3495 (Part 1- 3), 1992. It was observed that the produced bricks had an average density of 2015–2057 kg/m³ and a 4–6% water absorption rate. AFSB’s thermal conductivity was between 0.32 and 0.40 W/(m.K). The developed bricks exhibited a 57% reduction in embodied energy compared to burnt clay bricks and 12% compared to fly ash bricks. Experimental analysis validated the high performance and sustainability of the developed low-carbon, energy-efficient alkali-activated bricks, manufactured using industrial byproducts, demonstrating enhanced mechanical strength, durability, and a significantly reduced carbon emission.</p>