This study explores the relationship between language competence and intercultural communicative competence (ICC) among English as a Foreign Language (EFL) learners through a mixed-methods approach. A sample of 196 Chinese EFL learners was divided into three proficiency groups (low, intermediate, and high), with data collected through Likert-scale questionnaires and semi-structured interviews involving 16 participants. Quantitative analysis revealed that higher language proficiency is linked to improved overall ICC scores and its specific dimensions. The Kruskal-Wallis H test confirmed significant differences in overall ICC, attitude, and skill across proficiency levels, with attitude showing the strongest effect. Spearman's correlation analysis demonstrated small but significant positive correlations between English proficiency and overall ICC, attitude, and skill. Qualitative findings further enriched the quantitative results, emphasizing the foundational and catalytic role of language competence in enhancing ICC and its dimensions. However, participants acknowledged that language competence alone is insufficient for fully successful intercultural interactions. This study expands Byram’s model by offering detailed insights into the intricate relationship between language competence and various ICC dimensions. The study recommends that to fully cultivate ICC, it is essential to integrate the development of language competence into instructional practices.