Because of the increasing demand for energy, Li–O2 batteries have emerged as encouraging energy storage systems, because of their exceptional energy potential. However, the sluggish reactions caused by the inactive decomposition of the insulating discharge products are primarily responsible for disrupting their reversible operation. Herein, we report the direct application of hemoglobin (Hb) protein into carbon nanotubes (CNTs) via a facile fabrication way for efficient Li–O2 cell reactions. Our research indicated that Hb protein is an emerging environmentally friendly and abundant catalyst candidate with auto-oxygen binding properties. The protein was successfully infiltrated into CNTs via capillary force to fabricate proteinated CNT cathode materials. Compared with the cells featuring pristine CNTs, those featuring proteinated CNTs presented reversible performance and stable cyclability with low overpotential, because of the protein sources serving as a catalyst in the charge region. Our results suggest that proteins can be used to develop catalysts using an economic and environmentally friendly method. Moreover, our findings contribute to the progress of Li–O2 batteries as next-generation energy storage.