Dennie was on March 30, 1885, in Concord, Massachusetts. He attended public schools in Brockton, Massachusetts, and Williston Seminary—now known as Williston Northampton School—in Easthampton, Massachusetts. Dennie served as the athletic director as Missouri Mines until 1928, when he was appointed assistant professor of mathematics at the school. He died on January 13, 1952, in Rolla.[2]