In recent years, automotive manufacturers have increased their use of natural fiber composites to reduce vehicle weight and improve carbon footprint. However, natural fibers have lower thermal stability than many synthetic fiber alternatives, limiting their application to low‐processing temperature polymers and low‐temperature automotive environments. Pyrolysis of biomass yields a porous substance called biocarbon, which has superior thermal performance and hydrophobicity than biomass. This study evaluated the effects of biocarbon pyrolysis conditions and biomass source on the properties of biocarbon powders and the performance of biocarbon as a reinforcing agent in thermoplastic composites. Hybrid biocarbon‐glass fiber polyamide‐6 composites were generated with varying loading level and biocarbon type. Composites were evaluated in terms of mechanical (tensile and impact), morphological (scanning electron microscope), and thermal performance (thermal gravimetric analysis [TGA] and differential scanning calorimetry [DSC]); the chemical characteristics (X‐ray photoelectron spectroscopy and Fourier transform infrared) and thermal performance (TGA and DSC) of biocarbon powders were also determined. A 10% increase in the loading level of biocarbon resulted in a 7%–10% improvement in composite strength. Biomass source affected the thermal stability of a biocarbon powder. Coconut‐based biocarbon composites exhibited thermal performance comparable to materials currently used in automotive fan‐and‐shroud applications, suggesting that biocarbon composites have the potential for use as low‐density, high‐temperature automotive materials.