In 2018, 13.3% of culturally and linguistically diverse (CLD) families with international marriages had at least one child with a disability enrolled in South Korean public schools. Increasing school diversity requires special education teachers to bring new professional knowledge(s) and identities to meet the unique needs of CLD students with disabilities. Drawing on an interdisciplinary lens informed by disability critical race theory and cultural-historical activity theory, we conducted an instrumental case study to investigate the systemic contradictions that special education teachers experience in serving CLD students with disabilities. The results highlight how the intertwining of ethnicity-based racism, monolingualism, and patriarchal ideology shapes (in)visible deficit ideologies that mediate teachers' everyday interpretation, pedagogical practices, evaluation, and communication. Coupled with harmful deficit ideologies, the lack of systemic support in special education policies and practices consolidates the interlocking marginalization of CLD students with disabilities and their families at the intersection of language, culture, and other identity badges.