The use of proteins as biological tools and, therapeutic agents is limited due to the fact that proteins do not effectively cross the plasma membrane of cells. Here, we report a novel class of protein transporter molecules based on protein transduction domain mimics (PTDMs) synthesized via ring opening metathesis polymerization (ROMP). The PTDMs reported here were specifically inspired by amphi-philic peptides known to deliver functional proteins into cells-via noncovalent interactions between the peptide and the cargo. This contrasts with peptides like TAT, penetratin, and R9, which often require covalent fusion to their cargoes. Using the easily tunable synthetic ROMP platform, the importance of a longer hydrophobic segment with cationic guanidinium groups was established through the delivery of EGFP into Jurkat T cells. The most efficient of these protein transporters was used to deliver functional Cre Recombinase with similar to 80% knockdown efficiency into hard to transfect human T cells. Additionally, a C-terminally deleted form of the transcription factor Runxl (Runxl.d190) was delivered into primary murine splenocytes, producing a 2-fold increase in c-Myc mRNA production, showcasing the versatility of this platform to deliver biologically active proteins into hard to transfect cell types.