Self-Regulated Learning (SRL) is widely acknowledged as essential for educational achievement and fostering continuous learning skills (Taranto & Buchanan, 2020). As a result, there has been a marked escalation in embedding SRL criteria within academic curriculums, including primary education (De Smul et al., 2020; Heirweg et al., 2021). However, implementing SRL poses a significant challenge for educators, as it requires them to focus not just on delivering content but also on guiding students through the process of strategic learning. Teachers require specialised knowledge and expertise in effectively teaching SRL (De Smul et al.,2019). Understanding how to offer teachers support for effectively implementing SRL into classroom settings represents a vital area for future research (Dignath, 2021; Greene, 2021; Karlen et al., 2020). To this end, the current study investigated teachers' understanding of acquiring professional expertise in implementing SRL within Grades 5 and 6 classrooms. The research was conducted in a Catholic primary school in Victoria, Australia, employing a comprehensive SRL approach to teaching and learning practices. To gather insights from the participants, unstructured interviews were conducted. The methodology of Classic Grounded Theory (Glaser & Strauss in 1967) was applied to identify, conceptualise, and examine the participating teachers' perspectives. This study demonstrated the preference among teachers towards a multifaceted approach to SRL-focused professional development (PD) for enhancing critical aspects of teacher knowledge they deemed vital for SRL implementation. Furthermore, the findings emphasised the significance of teachers participating in training sessions to enhance their SRL content knowledge, team teaching opportunities centred on SRL pedagogical content knowledge and teacher coaching that emphasised teachers' experiences with practising SRL. The research underscored professional expertise in SRL implementation as an incremental process of cultivating specific areas of professional knowledge that relied on diverse approaches to PD and required a sustained approach.