Malaria parasites rely on an inner membrane complex to maintain structural integrity and motility. In this study, we identified the function of the IMC1j protein, a member of the alveoli family, during the invasive stages of Plasmodium berghei. Our findings indicate that knocking out or deleting the C-terminal region containing the coiled-coil domain of the IMC1j protein negatively impacts schizogony, ookinete morphology, motility, and infectivity. Additionally, IMC1j interacts with ISC1 and TubD through its IMCp domain to regulate the subpellicular network. These data demonstrate that the IMC1j protein is a crucial alveoli member for maintaining the structural integrity of the parasite.