Coating of the biodegradable metals represents an effective way of modification of their properties. Insufficient biological, mechanical, or degradation performance of pure metals may be enhanced when the proper type of organic polymer coating is used. In our previous work, the significant effect of the polyethyleneimine (PEI) coating not only on the rate but also on the type of corrosion was discovered. To bring a comprehensive overview of the Fe-PEI system performance, iron-based biodegradable scaffolds with polyethyleneimine coating were studied and their cytocompatibility and hemocompatibility, and mechanical properties were evaluated and discussed in this work. Electrochemical impedance spectroscopy (EIS) measurements were conducted for further study of material behavior. Biological analyses (MTS assay, fluorescent imaging, hemocompatibility tests) showed better cell proliferation on the surface of Fe-PEI samples but not sufficient overall cytocompatibility. Good anti-platelet adhesion properties but higher hemolysis when compared to the pure iron was also observed for the coated samples. Mechanical properties of the prepared Fe-PEI material were enhanced after coating. These findings suggest that the Fe-PEI may be an interesting potential biomaterial after further composition optimization resulting in lower cytotoxicity and better hemocompatibility.