Steel has been extensively utilized in vascular implants due to its mechanical strength, corrosion resistance, and clinical reliability. However, concerns regarding thrombogenicity and vascular injury have limited its long-term performance. A critical factor for the success of metallic implants is endothelialization, which prevents thrombosis, restenosis, and promotes implant integration. This study explores the use of endothelial cells (HUVECs) laden with superparamagnetic iron oxide nanoparticles (SPION) to culture on magnetic stainless steel (MS) surfaces. The objective was to investigate the effect of a weak magnetic field generated by MS on HUVEC attraction, comparing it with non-magnetic stainless steel (SS) and SS with an external neodymium magnet under static and flow culture conditions. The results demonstrated that MS surfaces, influenced by SPION, facilitated significantly improved HUVEC adhesion and focal adhesion point formation compared to SS and SS with an external magnet. Profilometric analysis revealed sharper topographical features on MS surfaces, which, despite their roughness, did not hinder cellular adhesion but instead promoted cell spreading and increased focal adhesion strength. Under static conditions, MS surfaces exhibited enhanced cytoskeletal remodelling and stronger focal adhesion formation. However, under flow conditions, the benefits were less pronounced, indicating the need for further optimization of surface features and magnetic properties to improve endothelial retention in dynamic environments. This research provides valuable insights into SPION-mediated endothelialization for magnetic stainless steel implants, highlighting their potential for enhancing biocompatibility and long-term performance in vascular applications. Further optimization is necessary to fully realize their potential in dynamic physiological settings.