The distortion of corner-sharing octahedra in isovalent perovskite transition-metal oxide interfaces have proven to be an excellent way to tailor the electronic and magnetic properties of their heterostructures. Combining depth-dependent magnetic characterization using polarized neutron reflectivity (PNR) and theoretical calculations (density functional theory), we report interface-driven magnetic exchange interactions due to modification in the octahedral rotations at the interfaces of the isovalent La_0.67Ca_0.33MnO₃/La_0.67Sr_0.33MnO₃ heterostructures. PNR results determined a length scale of ~8 unit cells at the interface, which demonstrated a modification in magnetic properties. The results also predicted a low-temperature exchange bias for these ferromagnetic heterostructures with a maximum exchange bias for the heterostructure, which showed an enhanced antiferromagnetic coupling at the interfaces.