2-Acetylpyridine-N(4)-morpholine thiosemicarbazone (HAcpMTSc) was synthesized and investigated as an inhibitor for mild steel corrosion in acid media. Various concentrations of the inhibitor in 1 M HCl solution were tested, and the corrosion inhibition efficiency to mild steel was estimated by means of weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy. The adsorption equilibrium constant (K-ads) and standard free energy of adsorption (Delta G degrees(ads)) were calculated. The nature of inhibition was studied by various spectroscopic techniques such as UV-visible, FTIR, and EPR spectroscopies and by using surface analysis methods (i.e., SEM-EDS).