Pt-M@FP-MWNT catalysts (M = Ru, Ni, Co, Sn, and Au) were prepared by one-step γ-ray irradiation. Two different types of functional polymers (FP), such as poly(vinylphenyl boronic acid) (PVPBAc) and poly(vinylpyrorridone) (PVP), were used as anchoring agents, when Pt-M nanoparticles were deposited on the multi-walled carbon nanotube (MWNT) using γ-ray irradiation in aqueous solution at room temperature. The obtained Pt-M@FP-MWNT catalysts were then characterized by XRD, TEM, and elemental analysis. The catalytic efficiency of the Pt-M@FP-MWNT catalysts was examined for CO stripping and MeOH oxidation for use in a direct methanol fuel cell (DMFC). The catalytic efficiency of the Pt-M@FP-MWNT catalyst for MeOH oxidation follows this order: Pt-Sn@FP-MWNT > Pt-Co@FPMWNT > Pt-Ru@FP-MWNT > Pt-Au@FP-MWNT > Pt-Ni@FP-MWNT catalysts. The CO adsorption capacity of the Pt-M@FP-MWNT catalyst for CO stripping is as follows: Pt-Ru@FP-MWNT > Pt-Sn@FP-MWNT > Pt-Au@FP-MWNT > Pt-Co@FP-MWNT > Pt-Ni@FP-MWNT catalyst.