This design-based research investigated the context and impact of a three-year practice-based professional development (PD) project introducing science teachers to pedagogical shifts required for full implementation and synergy among disciplinary literacy components of "Next Generation Science Standards" and "Common Core State Standards- Literacy." Participants included 42 middle school teachers from 12 primarily urban districts from one northeastern state. Researchers utilized a Theory of Change to guide the study. The interdisciplinary project team immersed teachers in experiencing innovative, standards-based, three-dimensional (3D) earth and space science (ESS) curricular units with embedded disciplinary literacy (DL) strategies. Teachers then adapted the 3D+DL units and implemented with students. Researchers used a convergent parallel mixed methods design to examine quantitative and qualitative data in the form of classroom observations to determine fidelity of implementation of 3D+DL practices, frequency of 3D+DL practices on the self-reported Science Literacy Survey, and focus group interviews to assess impacts of the PD project on teaching. Analyses revealed that teachers valued and embraced 3D+DL instructional shifts that supported teacher and student sensemaking in science. Teachers attributed project success to (a) project team collaboration to develop ESS units, (b) adaptability of ESS units, (c) explicit and direct instruction of 3D+DL, and (d) teacher sharing and reflecting on student success. The shift in teachers' understanding and practices of 3D+DL teaching and learning is likely attributed to teachers having the opportunity for sensemaking as learners with rigorous ESS units prior to implementing 3D+DL instruction with their students, which may provide guidance for future PD.