Poly(tetrafluoroethylene) (PTFE) powders were mounted on an electroless nickel/phosphorous (Ni/P) film on the surface of a carbon fiber by an electroless codeposition method. This type of carbon fiber filler, denoted FENCF, was then compounded with acrylonitrile-butadiene-styrene (ABS) for use in electromagnetic interference shielding. For the suspension of the PTFE powders, a surfactant was used. Although the adhesion between the electroless Ni/P-PTFE films and the fiber was reduced, the PTFE powders on the surface of FENCF reduced the torque values when compounded into the ABS matrix because of a self-lubricating effect. The two-step FENCF composites exhibited particularly significant advantages. The torque values for the two-step FENCF/ABS composites were about one-half of those for carbon fiber/ABS composites in compounding processes; in addition, the former had an average mean fiber length almost 2.5 times that of the latter. The multiyield phenomena in stress-strain curves of FENCF/ABS composites implied that the PTFE powders mounted on Ni/P films slid during stress-strain action. The electromagnetic interference shielding effectiveness of FENCF/ABS composites did not decrease significantly even though the PTFE powders formed a discontinuous phase on the electroless Ni/P films. The mechanical properties of FENCF composites were enhanced because of the larger fiber length.