Corrosion control of mild steel in seawater solution using Tobacco Leaf Extract (TLE) is investigated at different inhibitor concentration and temperature by weight loss method. Inhibitor performance increases with a decrease in temperature and increases with the rise of inhibitor concentration. Adsorption acts in accordance with Freundlich adsorption isotherm, having negative values of adsorption in high temperature, signifying a spontaneous and stable course of inhibition. In order to construct a relationship between the corrosion percentage data and independent variables, mathematical models were proposed with high correlation coefficients. Following the AM1-SCF method, quantum chemistry specifications of inhibitor were computed, for activation of the adsorption of the TLE molecules on the steel exterior.