Porous polyaniline–camphorsulfonic acid (PANI–CSA) counter-electrodes (CEs) for dye-sensitized solar cells (DSSCs) were fabricated by secondary doping-based polymerization with different porogen decomposition. The average pore diameter was ca. 50 and 150 nm for BPO and AIBN, respectively. The increased Brunauer–Emmett–Teller (BET) surface area of porous PANI–CSA CEs facilitated facile electron exchange between the CEs and the redox electrolyte, resulting in higher electro-catalytic performance than that of Pt-coated indium-doped tin oxide (ITO) CE. The porous PANI–CSA nanostructures with increased BET surface area exhibited an equivalent incident photon-to-electron conversion efficiency (IPCE) of 68.86% and a power-conversion efficiency (PCE, η) of 6.23% compared to DSSCs containing Pt-coated ITO CE (IPCE of 68.70% and η = 6.17%). It is noteworthy that the performance of DSSCs with porous PANI–CSA CEs represented a 101.0% relative efficiency compared to Pt-coated CEs.