This study investigates the innovative and sustainable use of crumb rubber (CR) and waste tire steel fibers (WTSF) in reinforced concrete beams. By addressing the concern of reduced shear capacity in rubberized reinforced concrete (RC) beams, the paper presents a sustainable approach that integrates WTSF and a hybrid treatment of CR involving temperature and fly ash. Six different concrete mixtures were developed, incorporating 15% and 25% CR as a replacement for natural fine aggregates, both with and without treatment, along with the addition of WTSF. The experimental program assessed the workability, mechanical properties, including compressive and split-tensile strength, and conducted four-point loaded flexural tests on rubberized RC beams designed to fail in shear, in order to investigate their shear behavior. A numerical study further analyzed this hybrid treatment approach across various parameters, including concrete mixture compositions, types of tensile reinforcement (conventional steel or Glass Fiber Reinforced Polymer, GFRP), transverse reinforcement types (conventional steel or GFRP), longitudinal reinforcement ratios, and the combined effects of treated rubber and WTSF. Key findings include a 10% higher compressive strength in the 25% treated rubberized concrete mixture (TRC25) compared to the 15% untreated rubberized concrete (URC15). Tensile strengths were significantly enhanced, with treated rubberized concrete beams containing WTSF at 15% and 25% showing tensile strengths 195% and 180% higher than normal concrete (NC), respectively. The inclusion of treated rubber and WTSF significantly improved shear capacities, with both 15% and 25% rubber content mixtures demonstrating substantially higher shear capacities than normal concrete. Toughness measurements indicated that treated rubberized concrete beams with WTSF at 15% and 25% rubber content showed toughness levels 15 to 18 times higher than NC. Beams reinforced with GFRP showed up to a 31% higher load capacity and greater deflection before failure compared to those with conventional steel reinforcement. The study highlights a beneficial shift from shear to flexural failure modes due to the combined effects of treated rubberized concrete and WTSF incorporation.