Movement Competence (MC) can be defined as the development of skill proficiency to ensure successful performance in a range of physical activities. Developing children’s MC is important for teachers, but also for coaches, researchers, athletic therapists and physiotherapists. One key construct of overall MC are fundamental movement skills (FMS). Research has highlighted a low level of FMS proficiency in Irish children, emphasising the need to further refine, implement and evaluate the recently developed Moving Well-Being Well (MWBW) intervention among 1st and 2nd class primary school children. Findings from Phase One of this PhD study indicate that the MWBW intervention significantly improved overall FMS proficiency (22.79%), confidence, enjoyment of, and engagement in physical education among the participating children. A number of challenges to successful implementation were also identified, such as, the school calendar and teacher fidelity, with findings suggesting that teacher’s fidelity had a direct impact on overall FMS improvement. Recent literature has suggested that the definition of MC is evolving to incorporate both fundamental and functional movement skills. Despite this evolution in the way MC is being viewed, as well as the literature demonstrating the interdependent relationship between the two constructs, no practical, real-world tool has yet combined them together as one assessment. Phase Two of this research project aimed to design such a tool, using a Delphi process, including a panel of worldwide experts from numerous fields of expertise. Following the design of the tool, it’s structural and convergent validity was examined. Findings suggest that the tool offers a time efficient, ecologically valid and specific alternative to current instruments such as the TGMD-3 and FMSTM, combining two essential constructs of children's motor competency.