Students designated as English learners and the broader group of multilingual learners continue to face restrictive learning environments in secondary classrooms despite existing research that demonstrates how integrating literacy development with authentic and relevant disciplinary learning benefits multilingual learners and all students. To address this issue, an interdisciplinary team of biliteracy and secondary content method scholars and teacher educators used funding through the U.S. Department of Education's National Professional Development Program to (1) articulate a cohesive framework that integrates "biliteracy" with disciplinary learning through research-based instructional practices and (2) explore how English, math, and science secondary content method instructors "apply" this framework when working with preservice teachers. The researchers connected translanguaging pedagogy, content and language/literacy integrated approaches, and a practice-based teacher education model to develop the Biliteracy and Content Area Integrated Preparation (BCAIP) Framework. They found that participating content area secondary method instructors made progress toward applying the BCAIP framework by building upon what they already do in support of diverse learners (i.e., foundational pedagogies) as they shifted toward biliteracy-oriented pedagogy. The authors argue that situating translanguaging in a disciplinary learning context better positions secondary teacher educators to transform how they prepare preservice teachers to serve multilingual learners.