Born in Pinopolis, son of Senator Edward James Dennis and Ella Mae Coney Dennis.
Educated at Furman University, A.B., 1936; University of South Carolina, LL.B., 1940; Georgetown University Law School, 1936–37. Admitted to the Bar, 1940. Honorary Degrees: Medical University of South Carolina, L.H.D., 1973; University of South Carolina, D.L., 1973; Clemson University, D.L., 1981; The Citadel, D.L., 1981; Charleston Southern University, D.L., 1989.
Practiced in Moncks Corner, 1940–92, senior partner in the firm of Dennis and Dennis. Former President, Berkeley County Bar Association. Member, S.C. Judicial Council, 1973–85. Farmer and cattleman, Stoney Landing Plantation.
State Senator, 1942–88; President Pro Tempore of the Senate, 1984–88; Chairman, Senate Finance Committee, 1972–88. State Representative, 1938–42. Board Member: State Budget and Control Board, 1972–88; S.C. Wildlife and Marine Resources Commission, 1972–85; S.C. Educational Television Commission, 1973–74.
Trustee, Medical University of S.C., 1961–72; Furman University, 1965–69; Baptist College at Charleston (now Charleston Southern University), 1971–76.
Enlightened statesman of South Carolina; progressive champion of fiscal responsibility; and premier wildlife conservationist.
Married: Natalie Brown. Six children: Rembert, Jr.; Natalie Dorn; E.J.; Mary Kathryn (deceased); Luke; and Beatrice.