Provided is a simple, fast, scalable, and environmentally benign method of producing a graphene-reinforced polymer matrix composite directly from a graphitic material, the method comprising: (a) mixing multiple particles of a graphitic material and multiple particles of a solid polymer carrier material to form a mixture in an impacting chamber of an energy impacting apparatus; (b) operating the energy impacting apparatus with a frequency and an intensity for a length of time sufficient for peeling off graphene sheets from the graphitic material and transferring the graphene sheets to surfaces of solid polymer carrier material particles to produce graphene-coated or graphene-embedded polymer particles inside the impacting chamber; and (c) forming graphene-coated or graphene-embedded polymer particles into the graphene-reinforced polymer matrix composite. Also provided is a mass of the graphene-coated or graphene-embedded polymer particles produced by this method.