To combine low cost, good mechanical properties, and antibacterial activity in one material, a nonquaternized polymeric biocide, i.e., poly[2-(tert-butylamino)ethyl methacrylate] (PTBAEMA), was dispersed within a commodity plastic, i.e., polypropylene (PP). The high immiscibility of the two polymers was tackled by reactive compatibilization and thus by reaction of commercially available maleic anhydride grafted polypropylene with primary amine-end-capped PTBAEMA. This reactive polymethacrylate was synthesized by atom-transfer radical polymerization with an azide-containing initiator. The azide end group was converted into a primary amine by the Huisgen [3 + 2] cycloaddition of propargylamine. The accordingly formed PP-g-PTBAEMA copolymer was melt dispersed within neat PP and processed as fibers, whose antimicrobial properties were assessed by the viable cell counting method against Escherichia coli. The antibacterial activity was long-lasting as a result of the anchoring of the PTBAEMA chains onto PP, which prevented them from being released from the surface of the fibers.