Controlled self-assembly (SA) of proteins offers the possibility to tune their properties or to create new materials. Herein, we present the synthesis of a modified human insulin (HI) with two distinct metal-ion binding sites, one native, the other abiotic, enabling hierarchical SA through coordination with two different metal ions. Selective attachment of an abiotic 2,2′-bipyridine (bipy) ligand to HI, yielding HI-bipy, enabled Zn^II-binding hexamers to SA into trimers of hexamers, [[HI-bipy]₆]₃, driven by octahedral coordination to a Fe^II ion. The structures were studied in solution by small-angle X-ray scattering and on surfaces with AFM. The abiotic metal ligand had a higher affinity for Fe^II than Zn^II ions, enabling control of the hexamer formation with Zn^II and the formation of trimers of hexamers with Fe^II ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine.