This study employed a blended approach to form an extensive assessment of the pedagogical suitability of data-driven learning (DDL) in Taiwan's EFL grammar classrooms. On the one hand, the study quantitatively investigated the effects of DDL compared with that of a traditional deductive approach on the learning motivation and self-efficacy of first-year college students majoring in English. On the other, it qualitatively examined a group of early-career teachers' (ECTs') hands-on experience of teaching DDL to these students. The research results via t-tests show that only those who received DDL treatment have enhanced learning attitudes in general. No significant differences, however, were found between the effects of these treatments in a multivariate analysis test of covariance. In contrast, qualitative inquiry shows that, despite facing technical difficulties and increased workload, the ECTs found their DDL teaching experience innovative and interesting, believed in its effectiveness in grammar learning, and judged it to transform Taiwanese students' grammar learning patterns from passivity to active engagement. This article concludes with suggestions for future DDL applications and investigation in the EFL grammar classrooms of Taiwan.