Regenerated cellulose fibers are required for widespread antibacterial applications across various fields. N-halamines have been extensively studied and are regarded as a promising candidate for antibacterial purposes. In this work, we focus on investigating the chlorination performance of urea-formaldehyde resin microspheres (UFRs) and using them as antibacterial additives incorporated into the spinning dope to fabricate antibacterial viscose fibers. UFRs exhibited rapid and repeatable chlorination capabilities while maintaining storage stability across various environments. Chlorinated UFRs exhibit potent broad-spectrum antibacterial activity and demonstrate low cytotoxicity toward mammalian cells. With 1, 3, and 5 % additions of UFRs in the viscose spinning dope, all the viscose spinning dope showed negligible changes in viscosity while ensuring long-term stability without any particle sedimentation. Viscose fibers bearing UFRs after chlorination exhibited high antimicrobial activities and renewable antimicrobial properties against bacteria and fungi while maintaining good foundational properties.