Hybrid composites are very promising materials for the next generation high performance electrochemical supercapacitors. We have designed a hybrid composite electrode of heteroatom doped carbon with polyaniline (PANI) for supercapacitor. In order to dope heteroatoms in carbon, we have selected sulfonated PANI as a precursor and its carbonization resulted in N, S and O doped carbon (CNSO). CNSO-PANI hybrid composite has been synthesized by polymerizing aniline with CNSO via aqueous polymerization. Electrochemical performance of CNSO-PANI has been evaluated by cyclic voltammetry, charge-discharge cycling and electrochemical impedance techniques. CNSO-PANI has yielded a higher capacitance value of 372F g−1 compared to pristine PANI (200 F g−1) at 0.8A g−1, which indicates that the performance of PANI has been enhanced by the introduction of CNSO. This composite electrode has also exhibited excellent charge-discharge cycling stability, retaining over 78% of its initial capacitance after 6000 cycles with a coulombic efficiency of 99–100%, which is still 45% larger than the initial capacitance of pristine PANI. A phase angle value of 85° from the Bode plot has provided additional evidence of good capacitor behavior for the CNSO-PANI. The results demonstrate that PANI could be effectively utilized with the assistance of CNSO in supercapacitor.