A highly sensitive electrochemical sensor based on immobilization of a newly synthesized urea functionality containing surfactant, 1-(2, 4-dinitrophenyl)-dodecanoylthiourea (DAN), possessing soil fertility enhancing characteristics, was developed for the detection of Hg(II) using cyclic, square wave and differential pulse voltammetry. Under suitable experimental conditions, calibration plot with a good linearity up to 2 μg/L was obtained with a detection limit of 0.64 μg/L and sensitivity of 0.164 μAL/μg in doubly distilled water at accumulation time of 360 secusing square wave voltammetry. The proposed method was also used for the determination of Hg (II) in drinking and tap water samples with very good recovery data and relative standard deviation of less than 3.5%. The designed sensor exhibited remarkable electro-catalytic effect by dramatically boosting the signal of the analyte as compared to the bare electrode. Computational studies of the interaction of DAN and mercury were also performed. The theoretical results were found in good agreement with the experimental findings.