Youth who report prosocial relationships with natural mentors show increased social and academic success and life satisfaction. However, little research investigates how mentors impact aspects of youth identity such as athleticism or religiosity. The present study applies a Bayesian Additive Regression Trees (BART) analysis model to data from a national longitudinal study (N = 15,701) to predict specific outcomes in educational, athletic, and religious domains. This analytic approach is uniquely well-suited for accurately drawing conclusions within highly collinear, high dimensional datasets. Analyses included demographic variables and childhood base rates of academic success, fitness, and religious beliefs as covariates. Findings indicate that the presence of an academic mentor during adolescence longitudinally predicts educational attainment, while athletic or religious mentors did not have significant impacts in terms of increasing athleticism or religiosity. These results suggest that academic mentors may have more longitudinal impacts on student success than other types of mentors.