We present a resonant angle-resolved photoemission spectroscopy (ARPES) study of the electronic band structure and heavy fermion quasiparticles in CeRu₂Si₂. Using light polarization analysis, considerations of the crystal field environment and hybridization between conduction and f electronic states, we identify the d-electronic orbital character of conduction bands crossing the Fermi level. Resonant ARPES spectra suggest that the localized Ce f states hybridize with e_g and t_2g states around the zone center. In this fashion, we reveal the orbital structure of the heavy fermion quasiparticles in CeRu₂Si₂ and discuss its implications for metamagnetism and superconductivity in the related compound CeCu₂Si₂.