The escalating demand for infrastructure in rapidly urbanizing regions has intensified the depletion of natural resources and amplified industrial waste generation. This dual impact not only accelerates global warming but also exacerbates environmental degradation through increased carbon emissions. In response, this study explores a sustainable alternative by incorporating industrial by-products and recycled aggregates into geopolymer concrete (GPC) production. Specifically, cement was partially substituted with industrial waste materials—15% pozzolanic by-product and varying percentages (0–50%) of reactive alkaline residue—alongside a consistent 25% replacement of natural coarse aggregate with recycled concrete aggregate (RCA). The fresh and hardened properties of the resulting GPC were assessed through slump and compressive strength tests. Results indicated that increasing the proportion of alkaline residue adversely affected workability, while compressive strength exhibited significant enhancement, reaching up to 136 MPa compared to the baseline 75 MPa. These findings highlight the potential of geopolymer concrete utilizing secondary raw materials as a cost-efficient and environmentally conscious construction material. The use of such by-products not only mitigates solid waste accumulation but also contributes positively to the circular economy and low-carbon development strategies.