Here we give an overview of how a spin-polarized metastable helium beam may be used to characterize surfaces and interfaces relevant to spin injection from a ferromagnetic (FM) electrode to an organic semiconductor (OSC). Taking advantage of the extreme surface sensitivity of this technique, we show how information regarding the electronic and magnetic properties of FM/OSC interfaces may be obtained. We demonstrate how the spin polarization at the surface of a FM oxide―Fe₃O₄(001)―may be drastically enhanced through atomic adsorption. We also investigate the adsorption of copper phthalocyanine (CuPc) on Fe₃O₄(001) revealing that the CuPc molecular orbitals are spin polarized due to the magnetic interaction with the substrate, even for a relatively thick film of 5 nm.