This study aims to analyze the principal’s strategy for improving the quality of Deep Learning-based instruction at SMA Negeri 13 Surabaya, Strategic planning, Deep Learning deployment, Academic oversight, evaluation and assessment, and professional development for teachers, enabling and impeding conditions, and follow-up measures for ongoing improvement are the main topics of the study. A case study methodology combined with a descriptive qualitative design was used. Data were collected through semi-structured interviews, passive-participation observations, and documentation involving the principal, vice principal for curriculum, teachers, and students. Observations were conducted from 22 June to 5 September 2026. The Plan, Do, Check, Act (PDCA) framework was used as the substantive analytical framework. Data condensation, data display, cross-source comparison, and conclusion verification were used to examine the data. The findings show that the principal’s strategy operates as an integrated instructional leadership cycle. The Plan stage includes collaborative curriculum planning, analysis, teacher competency development, resource preparation, and quality targets. The Do stage translates the strategy into mindful, meaningful, joyful, collaborative, contextual, and student-centered learning supported by mentoring, learning communities, technology, and innovation. The Check stage uses academic supervision, classroom observation, diagnostic, formative, and summative assessment, curriculum evaluation, and reflection. The Act stage converts evidence into coaching, mentoring, IHT, workshops, MGMP, learning innovation, and subsequent improvement. The study concludes that the principal’s strategy is systematic, collaborative, evidence-informed, and continuous. Its main contribution is explaining how school-level leadership connects Deep Learning pedagogy with a continuous quality-improvement mechanism rather than treating Deep Learning as a classroom technique alone.