Injection molding and film drawing of polyamide (PA 12) with single and few‐layer functionalized graphene (FG) affords carbon/PA 12 nanocomposites with considerably improved property balance, unparalleled by other carbon nanofillers. As compared to carbon black (CB), expanded graphite (EG 60) and carbon nanotubes (CNT), the addition of FG such as thermally reduced graphite oxide (TRGO) and multilayer graphene (MLG 350) enables the simultaneous improvement of PA 12 matrix reinforcement, electrical conductivity and gas barrier resistance. Hence, FG/PA 12 composites are of interest for envisioned applications such as automotive fuel lines and packaging.