In the preparation of polypropylene (PP)-based nanocomposites, grafting end-functionalized PP to nano-sized fillers is a promising strategy to alleviate the compatibility and interfacial problems at once, while poor synthetic efficiency for the end-functionalized PP and its grafting has been a major issue to be addressed. Here, we synthesized functionalized PP with one or less silicon methoxy groups per chain by means of direct copolymerization using a Ziegler-Natta catalyst, and utilized it as a reactive matrix in melt-mixing with spherical SiO2 nanoparticles. In addition to its synthetic advantage, the introduction of a trace amount of reactive functional groups delivered several profitable consequences to the nanocomposites that are typical for end-functionalized PP, such as improved dispersion, dramatically accelerated crystallization, and mechanical reinforcements.