This extended study examines the impact of perceived instructional leadership on student engagement among international secondary schools in Jeddah, Saudi Arabia. Building on the ICMESSI2025 conference version, the paper incorporates recent empirical research (2022–2024) on digital leadership, cultural intelligence, and post-pandemic schooling. Using a mixed-methods design, data were collected from 500 students and 500 school leaders through surveys, followed by 20 semi-structured interviews for triangulation. Findings demonstrate that instructional leadership significantly predicts behavioral, emotional, and cognitive engagement, while digital leadership practices and cultural intelligence emerged as strong mediators. Results further suggest that gendered leadership practices, particularly within Saudi Arabia’s gender-segregated school context, have differentiated impacts on engagement. Compared to the earlier version, this paper extends the literature review, enriches the methodological explanation of reliability and validity procedures, and situates findings within global discourses on leadership effectiveness, digital pedagogy, and Vision 2030 reforms. The study concludes that instructional leadership not only enhances student engagement but also strengthens resilience, inclusivity, and equity in multicultural educational environments. Policy recommendations include embedding digital leadership competencies in leadership training, fostering gender-sensitive practices, and aligning school reforms with Saudi Arabia’s strategic national goals.