The behavior of mild steel (MS) corrosion in isopentyltriphenylphosphonium bromide (IPTPPB) as a green inhibitor into 0.5 M H₂SO₄ medium was examined by electrochemical techniques (galvanostatic (GP) and potentiostatic polarizations (PP), and electrochemical impedance spectroscopy (EIS)). Different concentrations of inhibitor were tried; maximum inhibition efficiency (99%) is obtained at 10⁻² M IPTPPB in 0.5 M H₂SO₄. The temperature and adsorption effect was examined by the temperature kinetic study and simulation. The polarization technique explains the mixed type behavior of the inhibitor. The nature of inhibition of MS-IPTPPB was also studied by energy dispersive X-ray spectroscopic (EDXS) technique using surface analysis methods; scanning electron microscopy (SEM) and at atomic force microscopy (AFM). The formation of the monolayer by self-assembly of surfactant molecules at metal surfaces increases the corrosion inhibition ability. Experimental conclusions were found to be consistent with the semi-empirical AM1 method and molecular dynamics (MD) simulation theoretical calculations findings.