Purpose: Classroom-based physical activity (PA) provides students the opportunity to achieve PA recommendations. However, limited research has examined grassroots efforts for classroom-based PA. The purpose of this study was to share the story of a grassroots initiative to increase PA during school, titled the 150 Project. Methods: Narrative inquiry was used to draw on participants shared experiences to bring the story into existence. Individual interviews were conducted (n = 4, project developers; n = 9, elementary classroom teachers). Interview data were coded to reveal connections and relationships between the participants' stories to form a narrative. Results: The narrative is told by explaining (a) challenge (achieve PA recommendations), (b) action steps (project design), (c) outcomes (student, teacher, and school), and (d) moral of the story (need valid data and increased advocacy for during-school PA). Discussion/Conclusion: The 150 Project successfully trained classroom teachers to increase PA and advocate for PE, but the project is unsustainable without additional support systems.