In recent years, the study of various forms of teachers’ leadership, student trust and engagement has gained increasing attention because these constructs are critical for understanding student success. However, investigation of how these constructs interact to shape students’ learning, particularly in the Ethiopian higher education contexts, remains underexplored. Addressing this gap, this study investigates how teachers’ full-range leadership influence student engagement in public universities of the regional state of Amhara, Ethiopia, with an emphasis on the mediating role of student trust in teachers in this relationship. Employing a mixed-methods research approach with a sequential explanatory design, the study involved 734 participants, including 719 undergraduate students (for quantitative data) selected through multistage stratified sampling and 9 undergraduate students and 6 university teachers (for qualitative data) selected through purposive sampling. Quantitative and qualitative data were collected using self-reported questionnaires and semi-structured interviews. While the quantitative data were analysed through descriptive statistics, one-sample t-test, and structural equation modelling, the qualitative data were analysed through thematic analysis. The study findings reveal that a moderate level of student engagement is often characterised by compliance with academic and institutional requirements. Regarding teachers’ full-range leadership, transformational leadership behaviours were strongly evident, which developed through ethical conduct, inspiration, and intellectual stimulation of students. Whereas transactional and passive/avoidant leadership behaviours received moderate and modest level ratings, mainly characterised by encouraged students’ conditional engagement and little support, respectively. Relatively, a higher level of student trust in teachers was evident, which developed through teachers’ competence, emotional support, and consistent treatment. The structural model findings further revealed that transformational teacher leadership behaviours show a significant, moderate and strong positive influence on student engagement and student trust in teachers, respectively, suggesting the effectiveness of transformational leadership behaviours for student engagement and trust in teachers. Conversely, transactional teacher leadership behaviours show a non-significant negative influence on student engagement and a significant, modest positive influence on student trust in teachers, suggesting a lesser contribution of teachers exhibiting transactional leadership behaviours for student engagement and trust in teachers. Passive/avoidant teacher leadership behaviours, on the other hand, show a non-significant positive influence on student engagement and a negative influence on student trust in teachers, reflecting a negligible contribution to both student engagement and trust in teachers. Additionally, student trust in teachers shows a significantly large and positive influence on student engagement, reflecting a very strong relationship. It also plays a partial mediating role in facilitating the influences of transformational teacher leadership behaviours on student engagement. Nevertheless, no mediating roles do student trust in teachers play in transforming the influence of transactional and passive/avoidant teacher leadership behaviours on student engagement. In conclusion, these findings underscore the importance of nurturing trust-based student-teacher relationships as a pathway for translating effective teachers’ leadership practices, particularly the transformational and, to a lesser extent, the transactional ones, into meaningful student engagement.