Nature has inspired scientists to develop green and sustainable nanomaterials with biomimetic functions. Particularly, biomimetic metallic nanostructures (biometal NPs) with unique optical, catalytic, and electrical properties have received tremendous attention in many fields, ranging from healthcare and agriculture to energy and environmental sciences. Biometal NPs synthesized by various natural resources such as plant extracts, biomolecules, bacteria, and even viruses possess unique biomimetic functions including but not limited to precise biorecognition, selfassembly, antibacterial/antiviral, and enzymatic properties. In this report, we first review the bioinspired synthesis of industrially important metal nanoparticles, followed by the discussion on how the different biological sources affect the biomimetic functions of the as-synthesized biometal NPs. Next, we review the recent advancement and applications of these biometal NPs in the fields of biomedical engineering and catalysis, which include the development of metallic nanobiosensors, biomedical imaging probes, nanotherapeutics (e.g., antimicrobial and photodynamic/photothermal therapeutic agents), as well as the design of multifunctional nanozymes and artificial metalloenzymes for chemical and biopharmaceutical industries. Finally, we highlight some of the latest advancements in nanobiomimicry and their emerging applications in clean energy, electronic devices, and data storage, which shows the game-changing role of biomimetic metallic nanostructures for various technological applications in the near future.