The primary aim of this study was to investigate the mechanical and durability characteristics of high-strength concrete (HSC) incorporating nano-sewage sludge. The HSC mixtures in this research were prepared using Ordinary Portland cement (OPC), fine and coarse aggregates, portable water, and chemical and mineral admixtures, including nano-sewage sludge at various replacement levels. To improve the workability of the concrete, a superplasticizer was incorporated and following the guidelines of IS 10262:2019, which specifies a mix design of M70 grade HSC with a water-to-cement ratio of 0.26. Cube and cylindrical beam specimens were cast to evaluate a range of combinations, focusing on both mechanical and durability properties. Nano-sewage sludge was used to replace cement partially at levels of 0, 2.5, 5, 7.5, 10, 12.5, 15, 20, 25, and 30%. The concrete’s mechanical and durability performance was assessed at 7, 28, 56, 90, 180, and 365 days post-casting. Tests included measurements of compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity, rapid chloride permeability, and sulfate expansion. The results indicated that the inclusion of nano-sewage sludge generally enhanced the mechanical and durability properties of the concrete mixes.