Nanotechnology is a vast field of science with the most vibrant and conspicuous applications. The green synthesis approach is cost-effective, eco-friendly, and produces the most stable metal-based nanoparticles without the use of toxic chemicals. This study presents the green synthesis of iron nanoparticles (FeNPs). For biosynthesis of FeNPs, Phoenix dactylifera extract was used as a reducing agent and iron sulfate heptahydrate (FeSO·7HO) was used as a substrate. FeNPs were characterized by different techniques including UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nano zeta-sizer analysis. The antimicrobial activity of FeNPs synthesized by using an aqueous extract of Phoenix dactylifera was evaluated against Escherichia coli, Bacillus subtilis, Micrococcus leutus, and Klebsiella pneumoniae. A notable color change from yellow to black confirmed the synthesis of FeNPs. The sharp peak at 450 nm UV-Visible spectroscopy confirmed the synthesis of FeNPs. FTIR showed the presence of O-H and C=C stretching due to the presence of phenol and alkene functional groups. The average size of FeNPs was 6092 d.nm. The results of antimicrobial activity showed that FeNPs exhibit different potential against different bacterial strains with a maximum 25 ± 0.360 zone of inhibition against Escherichia coli. Thus, green synthesized FeNPs could be used as potential antimicrobial agents.