This study provides an in-depth analysis of the changes in middle school students’ perceptions of student teachers following a four-week teaching practicum, focusing on the students’ perspective. A mixed-methods approach was used, involving 123 students from a university-affiliated middle school in South Korea who completed pre- and post-practicum surveys. Quantitative data were analysed using paired-samples t-tests, while qualitative data underwent thematic analysis. The findings revealed a statistically significant positive change (p < .001) in students’ perceptions across all affective domains, including ‘class enjoyment’, ‘relationship and communication’, ‘school life enjoyment’, and ‘classroom atmosphere improvement’, with the exception of ‘help with academic achievement’. The domain of ‘relationship and communication’ showed the largest effect size (d = 0.81). The qualitative analysis indicated that students experienced high satisfaction from forming horizontal relationships with the near-peer student teachers and from engaging with their novel teaching methods. These results suggest that the core value of the teaching practicum lies in fostering the affective domain rather than enhancing cognitive achievement. This study identifies key factors for a successful practicum from a learner-centred perspective and offers practical implications for creating a meaningful educational experience for both students and pre-service teachers.