Wellbeing literacy (WL) may be the missing ingredient required to optimally enhance or enable positive psychology intervention (PPI) effectiveness. This study involved Victorian government funded primary schools, including two rural, two regional, and two city schools; participants included 20 classroom teachers and 131 grade five and six primary school students. A brief online PPI was implemented by teachers for 10–15 min, three times per week, for six weeks. This paper examines quantitative data collected pre and post the six week intervention, and qualitative data gathered in week one of the intervention regarding intervention effectiveness. The aim is to examine if a brief online PPI effectively builds intentional emotional vocabulary use, and to discuss how on-line PPIs can be used in public health to improve young people’s WL. Considering evaluations of process effectiveness and outcome measures related to student emotional vocabulary use, results tentatively suggest that online PPIs can positively impact emotional vocabulary capability and intentionality. Multimodal communication was exercised during the PPI, suggesting that the brief online PPI format may provide a valuable tool to promote student WL.