The increasing municipal solid waste (MSW) has been a growing issue for the last few decades. Plastic waste is a major contributor to MSW, which involves high-density polyethylene (HDPE), polyurethane, low-density polyethylene, and polyethylene terephthalate, among which HDPE generates a large amount of waste. This paper aims to modify the base binder VG 30 with HDPE pyrolytic char and evaluate its rutting potential. The pyrolytic char is obtained from the pyrolysis of the HDPE plastic, and it was mixed with the base binder in proportions 5, 10, and 15% in a high-shear mixer to prepare HDPE char-modified binder. Physical testing, including rotational viscosity, tensile, softening point, and penetration tests, was carried out in the laboratory. A rolling thin film oven test (RTFOT) is used for testing the short-term aging (STA) of the binder. To evaluate the temperature and rutting susceptibility of the STA sample, the temperature sweep test and the multiple stress creep and recovery (MSCR) tests are conducted on a dynamic shear rheometer (DSR). The results show that the increasing content of HDPE char increases the stiffness and softening point of the modified bitumen, which leads to better stability and thermal resistance of binder. The HDPE char increases the temperature susceptibility of bitumen at high temperatures. The rutting susceptibility of the base binder is improved due to the addition of HDPE char, which affects extended road life. The modified binder also shows better suitability for higher traffic loading conditions compared to the base binder.