The Zn-ion micro-supercapacitor (ZMSC) is a promising candidate for developing miniaturized and integrated energy storage devices. To achieve high-performance functional groups with simple processing to composite with rod-like active PANI fibers, we prepared exfoliated graphene (EG) with an appropriate amount of O-containing functional groups. The appropriate O content simultaneously facilitated self-assembly of the EG and PANI fibers and maintained the electric conductivity of the composite, producing a free-standing EG/PANI film without additional conductive additives or current collectors. As an interdigital electrode for the ZMSC, the EG/PANI film showed ultrahigh capacitance of 1.8 F cm−2at 2.6 mA cm−2(361.3 F g−1at 0.5 A g−1) and landmark energy density of 755.8 μWh cm−2at 2.3 mW cm−2(148.2 Wh kg−1at 451.7 W kg−1). The facile preparation of the high-performance EG/PANI electrode provides a potential path for practical applications with ZMSCs.