In this article, we present a strategy for fabricating polypropylene (PP)/polypropylene-regrafted single-walled carbon nanotube (PP-re-g-SWNT) composites with a high loading of single-walled carbon nanotubes (SWNTs; 20 wt %). The PP-re-g-SWNTs were characterized by X-ray photoelectron, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis (TGA). The PP-re-g-SWNTs showed excellent interfacial adhesion and dispersion. Furthermore, PP molecules, about 72 wt % by mass, were homogeneously bonded onto the surface of the SWNTs according to TGA. In this hybrid nanocomposite system, the PP-re-g-SWNTs were covalently integrated into the PP matrix and became part of the conjugated network structure (as evidenced by differential scanning calorimetry and dynamic mechanical analysis) rather than just a separate component. Accordingly, the PP/PP-re-g-SWNT composites presented obvious improvements in mechanical properties and conductivity (from 10−10 to 10−2). Most importantly, the tensile and flexural strength of the PP/PP-re-g-SWNT composites did not exhibit an obvious downturn with the addition of 20 wt % SWNTs; this was contrary to documented results. We believe that these new observations were due to the novel structure of the PP-re-g-SWNTs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39817.