As more states in the USA require elementary schools to offer computer science (CS) education, teachers are expected to master the knowledge and skills to teach CS by integrating computational thinking (CT) into content areas. This study presented a research-practice partnership approach to support elementary teachers in a local school district with CT integration. Professional development (PD) followed the technological, pedagogical, and content knowledge (TPACK) framework, and three elementary teachers' PD and classroom implementation experiences were examined and reported as a multiple case study. Interviews, observations, and teacher artifacts and reflections were collected and analyzed. The cross-case analysis revealed that the teachers (1) had an improved understanding of how CS/CT connects with content areas and how to make alignments across content standards, (2) demonstrated concrete strategies for designing and implementing CT-integrated instruction with various coding tools, and (3) provided students with engaging and inclusive learning experiences using a range of pedagogies. The paper discussed the implications for CS education at the elementary level.