We investigate the electrical transport properties of multilayer graphene (MLG) following irradiation with Ar plasma. The plasma induces defects, including vacancies, voids, and nanoholes, which altered the resistance of the MLG. The resulting defect-rich MLG device exhibits an asymmetric ambipolar behavior, with a strong p-doping effect, which considerably deteriorates the electron conductivity, implies defect generation on the MLG surface. The pristine MLG was metallic; however, the resulting defect-rich MLG following plasma treatment exhibited a semiconductor-like temperature dependence of the resistance. Thus, MLG with morphological disorder exhibits a metallic-to-semiconductor transition in the resistance as a function of temperature.