Explanatory videos are central to digital and blended learning environments, especially in student-centered formats such as flipped classroom. Their instructional value depends not only on video design, but also on learners' ability to regulate their engagement with video-based content. Although research on flipped classroom, video analytics, and self-regulated learning has expanded considerably, less is known about how learning strategies designed for explanatory video use shape students' self-reported strategy use, log data-based video interaction, and learning gains in authentic K-12 classroom settings. The present study examined strategy-based support for explanatory video use in a quasi-experimental design with N = 410 secondary school students. Students in the strategy group received explicit guidance on video-specific learning strategies (e.g., note-taking, rewinding), whereas the non-strategy group completed the same learning activities without such guidance. Learning outcomes, self-reported strategy use, and log data comprising approximately 24,000 recorded video interactions were analyzed using hierarchical linear modeling. In addition, a newly developed Video Engagement Score (VES) captured overall behavioral engagement beyond isolated log variables. Students in the strategy group reported higher strategy use and showed more intensive video interaction, including more frequent pausing, rewinding, and longer viewing times. However, these changes did not translate into significantly higher learning gains. Across groups, only video viewing compliance predicted learning gains. The findings suggest that learning strategies can shape students’ engagement with explanatory videos, but that accessing the assigned videos, rather than assignment to the strategy group, was more closely associated with learning gains.