garrison graduated as valedictorian of the 1959 class of roanoke catholic high school, aged 17. he was president of his fraternity at the university of virginia, where he received an undergraduate degree in 1963, and then a law degree in 1966. from there he became an assistant commonwealth's attorney in his home town of roanoke, and by 1969, at age 27, became the youngest person elected as the commonwealth's attorney.