It takes 4 years of undergraduate education, 4 years of medical school, and 3 years of pediatric residency to become a general pediatrician, totaling at least 11 years. Further, most fellowship subspecialties last 3 years, increasing the time spent in training to about 14 years overall.t takes 4 years of undergraduate education, 4 years of medical school, and 3 years of pediatric residency to become a general pediatrician, totaling at least 11 years. Further, most fellowship subspecialties last 3 years, increasing the time spent in training to about 14 years overall.