Purpose: Given the unequal distribution of physical activity (PA) opportunities across middle schools, alternative options for promoting it should be explored. Faith-based schools are positioned to offer religious-themed PA interventions, yet few have been reported. We replicated previous research by investigating the effects of the Physical Activity for Lent (PAL) program on change in step count ([Delta]PA) and its associations with religiosity, enjoyment, and motivation (four subscales). Method: Over the 6-week Lenten season, three Catholic middle schools' students (n = 128) participated in a randomly allocated controlled crossover trial of a pedometer-based virtual journey that followed Jesus's life path. We used the Reliable Change Index (RCI), general linear mixed models, and logistic regression to identify changes (pre- to post-Lent) in the independent variables, and their association with [delta]PA overall and of being in the highest [Delta]PA tertile. Results: Between 11.6% (religiosity) and 34.7% (external regulation) of participants' scores changed. School (School 3 > Schools 1 and 2 by ~2,400 steps/day, p < 0.001) and grade (6th grade > 7th and 8th grades by ~2,500 steps/day, p < 0.001) -- but not religiosity, enjoyment, or motivation -- were significant predictors of [Delta]PA. As RCI for intrinsic motivation and identified regulation increased, students were more (OR = 2.49) and less (OR = 0.74) likely, respectively, to be in the high [Delta]PA tertile. Conclusion: Desirable [Delta]PA was situational (i.e., school, grade) and highest [Delta]PA tertile was associated with autonomous motivation. Faith-based PA interventions may need to include additional components to realize even greater gains.