The effects of human hair‐derived porous carbon (HHC) as an eco‐friendly reinforcing filler in the carbon fabric‐reinforced phenolic matrix composites (CPCs) are evaluated through micro‐structural characterization studies, tensile, and flexural tests, dynamic mechanical analysis, density and electrical conductivity measurements. Various interfacial interaction parameters like reinforcement efficiency, C‐factor, adhesion factor, and so on are also calculated and compared for understanding the effects of HHC in composites. Conventional hand‐layup technique is used for impregnation of slurry made of phenolic resin and 0–50 wt% HHC on carbon fabric followed by stacking and curing through hot pressing to get laminates of CPCs. Significant improvement in mechanical, viscoelastic and electrical properties are observed over unfilled composite for all investigated HHC loadings. However, 30–40 wt% filler loading gives the optimum balance of properties. The results show ∼15, 93, 50, 85, and 132% increase in tensile strength, Young's modulus, flexural strength, flexural modulus, and storage modulus, respectively. Moreover drastic gain (1,500%) in electrical conductivity and substantial enhancement in thermal stability of CPCs make HHC as a cheap alternative reinforcing filler for structural composite applications working under thermo‐mechanical loads. POLYM. COMPOS., 40:E1573–E1587, 2019. © 2018 Society of Plastics Engineers