This research introduces a novel approach for swiftly enhancing the electrochemical sensing capabilities of commercial screen-printed carbon electrodes through a rapid acid microwave-assisted functionalization of carbon nanofibers (f-CNFMW). A comparative analysis with the conventional refluxed system functionalization method (f-CNFRefluxed) was conducted to assess the electrochemical performance of the newly developed f-CNFMW. The voltametric study showed that f-CNF-MW significantly enhanced the electron transfer rate when testing common phenolic compounds such as hydroquinone, paracetamol, and caffeic acid. Moreover, the anodic oxidation potential for the majority of irreversible analytes was negatively shifted, indicating the high electro-catalytic activity of f-CNF-MW gained after this treatment, making it analytically useful for the electro-oxidation of some molecules that require high overpotential, mainly for purine bases and nitrite. Additionally, the developed f-CNF-MW exhibited remarkable resistance to fouling phenomena when exposed to bisphenol A and tryptophan, underscoring its potential for real-world applications. To sum up, this study highlights the potential of rapid microwave treatment in producing f-CNF-MW as a promising electrochemical nanomaterial, resulting in substantial improvements in electro-analytical capabilities compared to conventional methodologies.