There are few case reports of patients with hemiparetic stroke who had previously been diagnosed with poliomyelitis (polio). Herein, we present the case of an 84-year-old male stroke patient with right-sided hemiparesis and polio. He was infected with polio at age 6 and had severe right-leg palsy. He was able to walk independently, performed knee hyperextension, and walked using a cane prior to the stroke at age 84. He was transferred to our hospital 31 days post-stroke. At that time, manual muscle test (MMT) was Poor-to-Good for the right ankle muscles and Trace for the right hip and knee muscles. He required assistance from a therapist to walk even with grasping parallel bars because he could not hyperextend the right knee and the knee had collapsed. For physical therapy, he performed stretching, muscle strengthening, standing, and walking exercises. Consequently, he was able to walk with a walking frame independently at discharge (day 131 after the onset). He regained knee hyperextension and resolved the knee collapse. MMT for the right hip muscles became Poor. This hemiparetic stroke patient with polio had severe right leg palsy and consequently had trouble walking due to knee collapse. It is postulated that regaining the knee hyperextension enabled him to walk safely.