The graft polymerization of tert‐butyl acrylate (TBA) onto polyurethane (PU) was conducted to prepare a series of samples that was compared to a control series comprising a physical mixture of poly(TBA) and PU. Maximum tensile stress sharply increased because of chemical cross‐linking via poly(TBA), whereas tensile breaking strain slightly diminished by the grafted poly(TBA). Percent shape recovery at 10°C rapidly increased by the additional grafting of poly(TBA), whereas control series decreased with increases in TBA monomer content. Chemical cross‐linking from the grafted poly(TBA) was responsible for the enhancement of shape recovery. Low‐temperature flexibility tests from −35°C demonstrated that a proper composition of grafted poly(TBA) could enhance the flexibility of PU below 0°C. Overall, the grafted poly(TBA) greatly stepped up the maximum tensile stress, recovery capability to original form, and flexibility of PU at very low temperature.