<p>Concrete is one of the most extensively utilized construction material worldwide due to its cost-effectiveness and ease of production. Despite these advantages, it suffers from inherent limitations such as low tensile strength and a propensity for cracking, which compromise its long-term durability and structural integrity. Traditional reinforcement techniques like the use of steel rebars and synthetic fibers pose significant environmental and economic drawbacks including high carbon emissions and the depletion of non-renewable resources. Recycled Steel Fibers (RSFs) derived from industrial waste and discarded materials, emerge as a promising sustainable alternative. However, their optimal application in concrete remains underexplored. This study addresses this research gap by investigating the mechanical performance of concrete reinforced with varying proportions of RSFs, aiming to determine the ideal fiber dosage that maximizes both strength and durability. Through a structured experimental approach, concrete specimens with varying RSF content (0.5%, 1%, 1.5% and 2%) were tested for compressive strength, splitting tensile strength, flexural strength, toughness, ductility, cracking pattern and workability. The results revealed that RSF inclusion significantly enhanced mechanical properties, with the most favorable outcomes observed at fiber contents between 1.0% and 1.5%. Compressive strength increased by up to 57.24%, while flexural strength improved by 61.32%, demonstrating RSFs’ ability to mitigate cracking and enhance ductility. However, excessive fiber addition led to workability issues. These findings underscore the potential of RSFs to transform waste materials into valuable reinforcements for sustainable construction. By optimizing RSF utilization, this research contributes to the advancement of eco-efficient, durable, and resilient infrastructure, aligning with global sustainability objectives and circular economy principles.</p>