Using TRIUMF's off-line laser ion source test stand with a system of tunable titanium sapphire lasers, the polarization dependence of laser resonance ionization has been investigated using beryllium. A significant polarization dependence was observed for the excitation path 1S0 → 1P1∘ → 1S0, which are typical transitions for alkaline-earth and alkaline-earth like elements. This polarization dependence was further verified on Be radioactive isotopes at TRIUMF's isotope separator and accelerator facility (ISAC). Laser polarization was proven to be an important parameter in operating resonance ionization laser ion sources (RILIS). The polarization spectroscopy was performed off-line both on the 2p2 1S0 autoionizing (AI) state and high-n Rydberg states of the 2sns1S0 and 2snd1D2 series. The energy of the 2p2 1S0 AI state and ionization potential (IP) of beryllium were extracted as 76,167(6) cm−1 and 75,192.59(3) cm−1. Polarization spectroscopy can be used to determine the J values of newly found states in in-source spectroscopy of the complex/radioactive alkaline-earth like elements such as Ra, Sm, Yb, Pu and No. Display omitted •Polarization-dependent laser resonance ionization of Be in hot-cavity ion sources•Polarization spectroscopy on the 2p2 1S0 AI state and 2sns1S0 and 2snd1D2 series•2p2 1S0 autoionizing state energy measured to be 76,167(6) cm−1•Ionization potential of Be measured to be 75,192.59(3) cm−1•Polarization dependence observed for 9–11 Be isotopes in hot-cavity ion sources.