Potassium-ion batteries (PIBs) have attracted tremendous attention during the past several years due to their abundant reserves, wide distribution, fast ionic conductivity, and high operating voltage. The primary obstacle impeding the commercialization of rechargeable PIBs is the lack of suitable high-performance anode materials. Carbon materials, known for their environmental friendliness, abundant availability, and outstanding comprehensive performance, have received extensive attention because they can be utilized directly as anodes or serve as a constrained matrix for conversion-/alloying-type anodes to enhance the electrochemical performance. Structural tuning and morphological modulation are two common strategies for modifying carbon materials. In this review, the recent progress in carbon materials aimed at enhancing the performance of PIBs through the utilization of these two strategies is systematically summarized. First, the effects of structural tuning and morphological modulation on the electrochemical properties of carbon materials and the corresponding storage mechanisms are reviewed. Second, the performance improvement mechanisms of conversion-/alloying-type anodes utilizing carbon scaffolds based on these two strategies are systematically discussed. Third, the application of carbon materials based on various modification strategies in various advanced K⁺ storage devices is reviewed. Finally, the challenges and perspectives for the further development of carbon-based materials for PIBs are highlighted.