Hard carbon shows promise as a potassium-ion battery (PIB) anode, but its high capacity and rate property are limited by insufficient active sites and poor kinetics. Creating a porous channel structure offers an effective route, but such design often disrupts the development of intercalation sites critical for low-voltage plateau capacity, and may reduce the energy density of full cells. Herein, a staged pyrolysis strategy was developed to tailor foam-like carbon microspheres (FCMs) with controllable pseudo-graphitic domains by exploiting polymer with the temperature difference in pyrolysis. Such tactics perfectly retains abundant pseudo-graphitic domains and creates rich defect/pore structures, ensuring efficient K+ low-voltage intercalation and benefiting fast K+ transport. The optimized electrode exhibits balanced adsorption/intercalation capacity, delivering a large reversible capacity (386.7 mAh g−1 at 0.1C), outstanding rate performance (223.1 mAh g−1 at 4C) and excellent capacity retention (79.2 % over 2000 cycles at 4C). Additionally, the FCM-2//PTCDA full cell submits a high energy density of 198 Wh kg−1 and superb rate property/stability compared to same-type full cells. Tracked K-storage behavior confirmed the “adsorption–intercalation” mechanism and kinetic studies clarified that exact balance of defect, mesopore and pseudo-graphitic phase was crucial for the synergistic enhancement of adsorption/intercalation kinetics. This work opens up a unique method to tune the microstructure of hard carbon and offers design principles for developing practical anodes with synergistic storage behavior suitable for PIBs.