Metallic metamaterials that combine superelasticity, high energy density (enthalpy), and heavy load-bearing capacity have been long sought for applications in energy absorption, impact protection, and vibration control. However, achieving this combination remains elusive due to limitations of material strength and design paradigm. Here, inspired by DNA supercoiling, we report all-metallic metamaterials composed of helices that undergo hierarchical twist-buckling under compression. This supercoiled geometry synergistically enhances load resistance and energy storage while mitigating stress concentrations, enabling recoverable strains up to 50%, tripling the buckling strength and quadrupling the enthalpy of densely packed prismatic lattices. An accurate deep-buckling theory clarifies how global twist elevates strength and energy density, while local curvature ensures superelasticity. Using steel assemblies, we demonstrate robust cyclic superelasticity and create quasi-zero-stiffness isolators that maintain ultralow resonance frequency (f0 ≤ 2 Hz) while supporting 100–1000× higher loads than existing designs, bridging the critical gap between high load capacity and low-frequency isolation, and breaking through the theoretical limit of conventional springs. Our work establishes a general, scalable and manufacturable principle for superelastic metallic metamaterials, opening new pathways for advanced applications in vibration mitigation, energy absorption, and protective structures.