FeRh films, known as antiferromagnetic materials at low temperatures, exhibit unexpected ferromagnetic (FM) characteristics, unlike the bulk. The detailed temperature-dependent physical properties of FeRh films were examined to elucidate the causes. Temperature-dependent magnetic and electrical measurements showed that the coexistence of antiferromagnetic and residual FM states induces thermomagnetic irreversibility (e.g., spin-glass-like behavior) and negative magnetoresistance. Polarized neutron reflectometry (PNR) revealed the presence of non-uniform FM states at the interfaces. Additional temperature-dependent PNR profile and room temperature structural and spectroscopic analyses confirmed that the bottom FM region is correlated with structural distortion. In contrast, the top FM region is temperature-dependent and originates from non-stoichiometry.