The combination of attractive supramolecular interactions of a hydrophobic Au-I-metallopeptide with the shielding effect of flexible oligoethylene glycol chains provides access to a stepwise self-assembly of a Au-I-metalloamphiphile in water. Kinetic control of the supramolecular polymer morphology is achieved using a temperature-dependent assembly protocol, which yields low dispersity supramolecular polymers (metastable state I) or helical bundled nanorods (state II).