<p>This study investigates the corrosion inhibition performance of a green inhibitor derived from <i>Trifolium repens</i> (<i>T. repens</i>) extract for X60 carbon steel in a 1-M H₂SO₄ solution. The evaluation was conducted using electrochemical techniques [electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP)] complemented by surface analysis via scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results demonstrated that the extract acts as an effective mixed-type inhibitor, with its efficiency strongly dependent on concentration. A maximum inhibition efficiency of over 84% was achieved at an optimal concentration of 30 ppm. Surface characterization confirmed the formation of a protective adsorbed film on the steel surface, which significantly mitigated corrosion damage. Investigation of temperature effects (25–60°C) revealed a decrease in inhibition efficiency with rising temperature attaining 50% at 60°C, suggesting a physisorption-dominated adsorption mechanism. This was further supported by thermodynamic analysis, which showed an increase in the activation energy (<i>E</i>_a = 71.12 Kj&#xa0;mol⁻¹) for the corrosion process in the presence of the inhibitor. The adsorption process was found to be spontaneous and followed the Langmuir adsorption isotherm with (<i>ΔG</i> =  − 27.52 Kj&#xa0;mol⁻¹). This work conclusively establishes <i>T. repens</i> extract as a potent, eco-friendly, and cost-effective corrosion inhibitor for carbon steel in acidic environments.</p>