The initiation, structure, and dynamics of defects control both the structure and physical properties of materials. In this work, kink band defects are systematically introduced into a lamellar poly(styrene-b-ethylene propylene) diblock copolymer by applying various rates and total strains of steady shear. However, kink bands are only produced when the shear strain exceeds a critical value. The mere existence of kink bands implies the presence of a preferential slip plane parallel to the lamellae, which we estimate exists within the polystyrene microdomains. Furthermore, our results regarding the dependence of kink band geometry on shear rate and strain suggest that these defects are formed by the rotation of lamellae. Based on a rotation mechanism, the characteristic size of the kink bands and their spatial distribution, it appears that preexisting defects initiate kink bands. Insights gained from steady-shear-induced kink bands are extended to oscillatory shear alignment of this high molecular weight diblock copolymer, allowing us to circumvent a previously reported shear-stabilized parallel-transverse biaxial texture.