The value of the strong coupling constant is key to understanding current high-energy experimental data. I will present a first-principles determination of αs using dedicated lattice-QCD techniques. The talk will focus on the methods that have enabled us to achieve sub-percent precision—our uncertainty is roughly half that of the combined phenomenological determinations—while keeping theoretical and other systematic errors sub-dominant. This result reduces theoretical uncertainties in high-energy experiments, enhancing prospects for new-physics discovery and enabling rigorous precision tests of the Standard Model, while confirming QCD as the theory of strong interactions across all energy scales.