Personal biography influences preservice classroom teachers' (PCT) perceptions and attitudes related to school-based physical activity promotion (SPAP). Using an uncontrolled prepost design, this study investigated associations between biographical variables and changes in PCTs' SPAP attitudes and perceived competence while enrolled in a 16-week SPAP course. PCTs (N = 201) completed baseline measures assessing biographical variables of year in school, sports participation, coaching/teaching experience, BMI, satisfaction with K-12 physical education (PE) and perceived physical activity (PA) competence, and prepost measures assessing SPAP attitudes and perceived competence. One-way repeated measures analysis of variance procedures showed statistically significant, positive changes in PCTs' scores on all SPAP measures. Mixed-model analysis of variance/covariance techniques indicated sport participation, teaching/coaching experience, PE satisfaction and perceived PA competence were associated with changes in SPAP scores. Results suggest PCTs' SPAP learning experiences should incorporate strategies for enhancing self-schemas and perceptions related to PE and PA. (Contains 3 tables.)