Emotional intelligence (EI) is widely known to be crucial for professional development in education, and it is a curricular component of Greek teacher education. Still, there is little information available on student teachers’ EI. The aim of this study was to explore whether student teachers’ trait EI can be developed through a two-week, EI-focused intervention. The study followed a quasi-experimental design with a mixed method approach, using the Trait Emotional Intelligence Questionnaire-Short Form (Greek version) (N = 42) and reflective emotion diaries (N = 19). The participants were third-year undergraduate students studying primary education and teaching at the University of Crete. While the results from the statistical analysis showed no development of student teachers’ trait EI, the findings from the thematic analysis of the reflective emotion diaries suggested that this intervention was beneficial, facilitating emotion identification and potentially enabling emotion regulation through increased self-awareness. The study concludes with a discussion of its limitations and practical implications for future intervention studies on EI.