Imidazolium-type metal-containing ionic liquid (IL) monomers and their corresponding poly(ionic liquid) (PIL) membranes coordinated with CuCl (PILM-Cu), FeCl (PILM-Fe), or ZnCl (PILM-Zn) were synthesized. The effect of metal ions on the antimicrobial activities against both () and () was investigated. Compared with pristine PILM-Br membrane, PILM-Cu, PILM-Fe, and PILM-Zn membranes exhibit enhanced antibacterial activities due to the attributes of both imidazolium cations and metal-containing anions. Furthermore, all of the metal-containing PIL membranes present low hemolysis toward human red blood cell and high long-term antibacterial stability, even after immersion in water for 90 days, demonstrating clinical feasibility in topical applications.