 After the war, Mann enrolled at the University of South Carolina School of Law where he was editor of the "South Carolina Law Review" and graduated magna cum laude in 1947 as a member of the Euphradian Society.He was admitted to the state bar the same year and established a private practice in Greenville.In 1948, Mann was elected to the South Carolina House of Representatives and he served for two terms until Governor James F. Byrnes appointed him as the circuit solicitor for the 13th judicial circuit of South Carolina to succeed Robert T. Ashmore in 1953.