The rapid growth in enrolment in undergraduate teacher training programmes calls for a pedagogical innovation geared towards effective participatory classroom instruction. The purpose of this mixed study was to explore classroom engagement experiences with large classes as lived by student teachers at the selected public universities in Uganda. The level of behavioural, cognitive, emotional and agentic engagement among student teachers was investigated, as well as their experiences with these domains. Consequently, data from hermeneutical phenomenological and crosssectional survey design was triangulated. Proportionate random sampling was used to select 396 student teachers and purposive sampling was used to select nine focus groups from the selected public universities. Manifest content analysis was used to describe and infer meaning from participants’ statements. According to the mean and standard deviation ratings, large classes performed unsatisfactorily in terms of overall classroom engagement (M=3.4, SD=0.9) and agentic engagement (M=2.7, SD=1.0). However, they acknowledged being behaviourally, emotionally and cognitively engaged (M=3.6, SD=0.8; M=3.6, SD=0.9; M=3.8, SD=0.8). Focus group narratives revealed inadequate class support, incivility, social presence and interaction, passivity and discomfort experiences as key themes that influenced the participants’ engagement levels. They felt less in control of their learning experiences and had limited opportunities to make decisions that affected their learning outcomes. Social and academic responsibilities like signing attendance sheets, taking notes and meeting with friends significantly maintained class attendance. It was recommended to improve the training of lecturers in effective engagement techniques for large undergraduate classes, and universities to invest resources in providing textbooks, reference materials and digital technologies to facilitate constructive learning and classroom participation.