Joseph Zajac was born and raised in New Jersey. He attended Boston College for undergraduate degree in biology and psychology. He attended Universidad Autonoma de Guadalajara in Mexico for medical school and then completed undergraduate medical education at Mt. Sinai School of Medicine in New York.
Dr. Zajac remained at the Mt. Sinai Hospital for two years in general surgery training. He then moved to Downstate/Kings County and completed his urology training in 1992.
He moved to Bronxville, NY to private practice in urology in 1993. He currently lives there with his wife Nancy and three children.