The microstructural and tribological effects of ion implanting C into Ti‐implanted, Fe‐based alloys are examined and compared to the influence of C introduced by vacuum carburization during Ti implantation alone. The amorphous surface alloy formed by Ti implantation of pure Fe increases in thickness when additional C is implanted at depths containing Ti but beyond the range of carburization. Pin‐on‐disc tests of 15‐5 PH stainless steel show that implantation of both Ti and C reduces friction significantly under conditions where no reduction is obtained by Ti implantation alone; wear depths are also less when C is implanted. All available experimental results can be accounted for by consideration of the thickness and Ti concentration of the amorphous Fe‐Ti‐C alloy. The thicker amorphous layer on samples implanted with additional C extends tribological benefits to more severe wear regimes.