We report secondary amide side-chain-bearing polyacrylates with tunable aqueous solubility and cellular interaction. Redox-initiated reversible addition-fragmentation chain transfer polymerization of methylamide ethyl acrylate (MAmEA) and ethylamide ethyl acrylate (EAmEA) yielded well-defined homopolymers. P(MAmEA) and P(EAmEA) possess high glass-transition temperatures compared to the equivalent alkylated polyacrylates. P(EAmEA) showed a degree of polymerization and concentration-dependent lower critical solution temperature (LCST) behavior, which can be fine-tuned over a biologically relevant range through copolymerization of both monomers. No cytotoxicity against NIH 3T3 and RAW 264.7 cell lines was observed. Detailed cellular interaction studies revealed cell associations for P(MAmEA) similar to poly(N-acryloylmorpholine), a well-known nonionic water-soluble polymer and colocalization of both homopolymers with lysosomes. Due to the simple access of these monomers, the aqueous solubility, cytocompatibility, and cellular interaction of the homopolymers, and the possibility to combine them with a large number of acrylates, they hold great promise to become suitable building blocks for biomedical materials.