The present article deals with the effects of deformable bearing shells on the performance of lobed slot-entry hybrid journal bearing systems. The influence of the deformation coefficient ( d c ) has been studied using the thin liner elasticity model, which measures the flexibility of the bearing liner. Recently, smart fluid, that is, electrorheological (ER) fluid has been used in various tribological systems to obtain better performance. Therefore, the influence of ER lubricant on the bearing performance characteristics has also been studied in this work. Bingham model constitutive relation has been used to analyze the non-Newtonian behavior of ER fluid. The performance of fluid film bearings is greatly influenced by the noncircularity of the bearings. Therefore, the behavior of deformable bearing shells in a slot-entry journal bearing for lobed conditions has also been studied in the present study. The results reveal that considering deformation in the bearing shell reduces the value of frictional torque, whereas the value of stiffness coefficients and stability threshold speed increases. However, ER lubricant enhances the value of film thickness, stiffness/damping coefficients, and stability threshold speed margin.