We integrated science, mathematics, and literacy through engineering design in professional development with 24 in-service middle school math and science teachers in rural Appalachia. Participants experienced engineering design as learners, developed lesson plans utilizing engineering design, and received pedagogical and content coaching. Participants valued being active participants in learning, collaborating with peers around the work of teaching, focusing on integrating content across subjects and students' learning of that content, and the sustained nature of TESAL where professional development was fully relevant and supportive to their work as classroom teachers. These strengths align directly with best practices for professional development and for overcoming the challenges of professional development specifically on math-science integration and engineering design instruction.