The field of talent development (TD) has benefitted from a burgeoning of research over the last couple of decades, including psychological factors associated with successful TD. However, there is a notable gap in the literature relating to how practitioner sport psychologists can implement this knowledge into their applied practice. To address this research-practice gap, this thesis adopts an action research approach to understand how sport psychologists can go about supporting effective TD of athletes. Within the thesis, I outline the four-stage action research process I undertook as a researcher-practitioner working within a professional men’s rugby league academy. The first stage included a process of planning an evidence-informed and contextually-relevant intervention through exploration of the existing literature to understand what evidence already existed in this area, and interviews with players at the academy to explore their experiences of this developmental stage in their careers. Specifically, I was able to identify demands, resources, and barriers experienced by players during their time in the academy. This information was used to inform the delivery of a solution-focused groupwork intervention to relevant stakeholders (including players, coaches and support staff, and parents) in the next stage of the process. I then went on to observe the impact of the intervention, focusing particularly on any learning and/or change action that had occurred. Finally, I spent time reflecting on how these outcomes had been achieved, through exploring the processes and mechanisms that underpinned the observed learning and change action. Through engaging in this four-stage process, I have been able to deliver real-world impact and positive change within the academy in which I was working, improve my own applied practice as a practitioner sport psychologist, and also produce new knowledge to help bridge the research-practice gap within TD.