The development of multifunctional polymer therapeutics aligned with circular chemistry principles requires renewable building blocks, efficient synthesis, and enhanced material longevity. Herein, we report a circular-by-design zwitterionic pseudodendrimer based on hyperbranched polyglycerol–polyoxazoline–lysine (hPG-b-POX-Lys) that integrates antimicrobial activity with targeted anticancer drug delivery. Hyperbranched polyglycerol, derived from glycidol feedstocks, was selectively mesylated and used as a macroinitiator for ring-opening polymerization of 2-ethyl-2-oxazoline, followed by lysine functionalization. The modular synthesis afforded the polymer in 76% yield with high functional density and minimal steps. The zwitterionic architecture exhibited intrinsic antibacterial activity against Staphylococcus aureus and Escherichia coli with low cytotoxicity. The nanostructure achieved high loading capacity (81.25%) for the CDK4/6 inhibitor palbociclib and enabled efficient in vitro delivery, improving selectivity toward cancer cells. This platform demonstrates a scalable strategy for multifunctional, circular nanomedicine design.