The establishment of a benign system for the nanoparticle (NPs) synthesis, is a key in nanotechnology for the environmental and health care industries. Therefore, enrichment of novel biological systems for the green synthesis is in significant demand, to lift up these compounds in the biomedical industries. The present work, reports the green synthesis of ZnO NPs, employing a novel thermophile, identified as Bacillus haynesii (GeneBank: MG822851) isolated from the leaf of date palm plant (Phoenix dactylifera), as an eco-friendly nanobiofactory. Physiochemical characterization of ZnO NPs (50 ± 5 nm in size), was achieved by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), diffuse reflectance UV-Visible spectroscopy (DR UV-Vis spectroscopy), Thermogravimetry analysis (TGA), scanning electron microscopy (SEM) and transmissiom electron microscopy (TEM). The morphogenesis and antimicrobial activity of synthesized ZnO NPs, was studied by evaluating the minimum inhibitory/bactericidal concentration (MIC&MBC) against Escherchia coli (8 and 16 mg/mL) and Staphylococcus aureus (4 and 8 mg/mL), respectively. The present study encourages the use of B. haynesii for the green synthesis of ZnO NP. To the best of our knowledge, this is the first report on the study of thermophilic, B. haynesii for green synthesis of NPs in general and ZnO NPs in particular.