A solid acid catalyst has been synthesized from lignin-derived carbon fiber via a straightforward sulfonation reaction. The carbon fiber (CF) and sulfonated carbon fiber (CF-SO3H) catalysts were characterized by different techniques like PXRD, TGA, TPD-MS, SEM, and XPS to understand the surface chemistry and the nature of sulfonation. It was confirmed that sulfonated sample bearing a high concentration of acid sites (1.86 mmol/g) possess sulfur in its surface in the form of sulfonic acid (-SO3H) groups. Its catalytic activity was studied using the esterification of oleic acid as an example of biodiesel production, where a quantitative yield of 92% ester was achieved at 80 oC for 4 hours with 10 % of catalyst (based on oleic acid mass used) and at a 10:1 molar ratio of methanol/oleic acid. More importantly, CF-SO3H showed excellent regenerability and stability during catalysis, demonstrating their potential use in the production of biodiesel. In addition, this material is obtained from low-cost lignin which could be a good alternative solid acid catalyst to produce biodiesel such that this fuel can compete with current fossil fuels.