A simplified theoretical model was developed to predict complex behavior in protein displacement systems of immobilized metal ion affinity chromatography (IMAC). In this paper, experimental techniques for estimating equilibrium parameters were developed. The equilibrium parameters obtained were used to simulate displacement processes and to investigate the effect of mobile phase modifier (MPM) gradients in the IMAC separating systems. In the induced MPM gradient conditions, the solute movement analysis was able to predict the displacement separation well characterized by the intersections of the operation line under the effective displacer concentrations. The theoretical and experimental results demonstrate the utility of the IMAC model in predicting induced mobile phase modifier gradients and complex behavior in metal affinity displacement chromatography. Furthermore, the development of a rapid method for obtaining displacement profiles facilitates methods development and optimization of IMAC displacement separations.