In the present article, we studied the corrosion inhibition of the pyridine Schiff base N, N<acute accent>-bis(4-dimethylaminobenzaldehyde)-2, 6-pyridinediamine (4-DMBPy) during the corrosion of mild steel AISI 1020 in a 0.1 M HCl solution. The electrochemical analysis by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) revealed that the Schiff base promotes a protective efficiency up to 81 % at 25 ppm, followed by a decrease at higher concentrations. The Schiff base - surface interactions follow a Freundlich isotherm, indicating a physical adsorption mechanism. The theoretical calculus by Fukui function and dual reactivity descriptors confirmed the physical interaction with mild steel and the low reactivity of the adsorbed species that led to corrosion protection affecting the cathodic and anodic reactions. The quantum calculations by density functional theory (DFT) indicated that protective efficiency decreases due to the tendency to interact with each other. These interactions led to the formation of molecular aggregates and a desorption process. Molecular dynamics (MD) simulations exhibited that the 4-DMBPy molecule preferred to arrange parallel to the Fe (110) surface through physical adsorption. The results were complemented by the scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and atomic force microscopy (AFM) analyses to reveal the further information about the corrosion process and the effect of the 4-DMBPy Schiff base as a corrosion inhibitor. C1 [Soliz, Alvaro] Univ Atacama, Fac Ingn, Dept Ingn Met, Av Copayapu 485, Copiapo 1530000, Chile. [Zamora, Pedro Pablo; Muena, Juan Pablo; Bieger, Klaus] Univ Atacama, Fac Ciencias Nat, Dept Quim & Biol, Av Copayapu 485, Copiapo 1530000, Chile. [Haribabu, Jebiti] Univ Atacama, Fac Med, Av Carreras 1579, Copiapo 1532502, Chile. [Haribabu, Jebiti] Chennai Inst Technol CIT, Chennai 600069, India. [Landaeta, Esteban] Univ Cent Chile, Escuela Ingn, Santa Isabel 1186, Santiago 8330563, Chile. [Arulraj, Arunachalam] Univ Tecnol Metropolitana UTEM, Fac Ingn, Dept Elect, Av Jose Pedro Alessandri 1242, Santiago 7800002, Chile. [Mangalaraja, Ramalinga Viswanathan] Univ Adolfo Ibanez, Fac Engn & Sci, Diagonal Torres 2640, Santiago 7941169, Chile. [Mangalaraja, Ramalinga Viswanathan] Univ Arturo Prat, Vicerrectoria Invest & Innovac, Ave Arturo Prat 2120, Iquique 1110939, Chile. C3 Universidad de Atacama; Universidad de Atacama; Universidad de Atacama; Universidad Central de Chile; Universidad Tecnologica Metropolitana; Universidad Adolfo Ibanez; Universidad Arturo Prat