This PhD project had two primary aims across two distinct phases. Phase one aimed to determine the contribution of Gaelic football participation to adolescents’ overall daily physical activity (PA) levels. Informed by phase one, phase two explored the coaching pedagogy being applied by youth Gaelic football coaches and examined the effects of a Game Based Approach (GBA) coaching intervention in a youth Gaelic football setting. There are over 100,000 coaches in Gaelic Games, supported by a coach development system that provides education opportunities for beginner to high performance coaches. The research carried out in this PhD project demonstrated that GBAs provide significantly more PA to players than traditional coaching approaches. Therefore, the findings of this research support the development of a GBA Coach Education Programme which would positively impact both player and coach development. The results from Phase 1 revealed that participation in Gaelic football provides an ideal opportunity for adolescents to accumulate PA. However, the amount of PA attained was insufficient to achieve the minimum daily guidelines for the majority of adolescents. Phase 2 determined that a GBA holds considerable potential to positively enhance the contribution of participation in youth Gaelic football to participants’ daily PA levels.