A high-performance biomaterial-based resistive switching (RS) device is fabricated by harnessing a thermally denatured protein (hexa-His-tagged recombinant molecular chaperone DnaJ (rDnaJ)) as a switching layer in a Cu/rDnaJ/Pt configuration on SiO2/Si substrate. The conductivity of the heat-denatured rDnaJ protein layer between the metal electrodes can be reversibly controlled to enable the formation/rupture of conductive Cu filaments by tailoring the metal chelating properties of the amino acid residues in the insulating protein matrix in a pH- and/or redox potential-dependent manner, giving rise to high-performance nonvolatile RS behavior. The rDnaJ-based RS device exhibits extremely low set voltage (∼0.12 V) and reset voltage (∼−0.08 V) with excellent uniformity, along with large memory window (RHRS/RLRS > 106) and long retention time (>106 s). In addition, the rDnaJ RS device, which is fabricated on a flexible poly(ethylene terephthalate) substrate, exhibits an uncompromised switching performance. Th...