Organic materials receive increasing attention as environmentally benign and sustainable electrode‐active materials. We present a conducting redox polymer (CRP) based on poly(3,4‐ethylenedioxythiophene) with naphthoquinone pendant group, which is formed from a stable suspension of a trimeric precursor and an oxoammonium cation as oxidant. This suspension allows us to easily coat the polymer onto a current collector, opening up use of roll‐to‐roll processing or ink‐jet printing for electrode preparation. The CRP showed a full capacity of 76 mAh g−1 even at a high C rate of 100 C in acidic aqueous electrolyte. These properties make the CRP a promising candidate as anode‐active material; a polymer–air secondary battery was fabricated with the CRP as anode, a conventional Pt/C catalyst as cathode, and sulfuric acid aqueous solution as electrolyte. This battery yielded a discharge voltage of 0.50 V and showed good cycling stability with 97 % capacity retention after 100 cycles and high rate capabilities up to 20 C. Breathing air into polymers: A polymer–air secondary battery was fabricated with the conducting redox polymer as anode, a conventional Pt/C catalyst as cathode, and sulfuric acid aqueous solution as electrolyte. This battery demonstrated good cycling stability with 97 % capacity retention after 100 cycles and high rate capabilities up to 20 C.