Hopper played collegiately at Mississippi State University, known as Mississippi A&M College at the time, and was a three-year letterman. A search of MSU athletic records from the period show that Hopper's first collegiate year was as a member of legendary MSU head coach C.R. "Dudy" Noble's 1924 team that won the last of A&M's six baseball championships in the Southern Intercollegiate Athletic Association.
Hopper became a player-manager with the Laurel Cardinals in 1929. He played for the Greensboro Patriots in 1930, but did not manage the team. He managed the Scottsdale Cardinals in 1931, and was then hired by the St. Louis Cardinals organization as a player-manager for the Elmira Red Wings. He managed the Greensburg Redwings of the Pennsylvania State Association to the league championship in 1934. After managing the Springfield Cardinals of the Western Association to a second-place finish in 1938, he was promoted to manage the Columbus Red Birds of the South Atlantic League in 1939. He was promoted to manage the Houston Buffaloes of the Texas League in 1942. Hopper joined the Brooklyn Dodgers organization in 1942. He managed the Mobile Bears of the Southern League in 1945, leading them to the league championship. He was promoted to become the manager for the Montreal Royals of the International League for the 1946 season. That year, Jackie Robinson, the first black player to integrate baseball since the 1880s, entered the Dodgers farm system and was assigned to the Royals. Hopper, who opposed integration of baseball at the time, asked Branch Rickey, the general manager of the Dodgers, to assign Robinson to a different Dodgers affiliate, but Rickey kept Robinson assigned to Montreal. Robinson reported that Hopper treated him well, and the Royals won the Governors' Cup as the International League champions. The Sporting News named Hopper the Manager of the Year for all of minor league baseball that season. Hopper recommended the Dodgers promote Robinson to the major leagues for the 1947 season. Hopper remained Montreal's manager through the 1949 season. Between 1946 and 1949, Hopper managed three Governors' Cup champions. In 1950, Rickey assigned Hopper to manage the St. Paul Saints of the American Association, as Walter Alston became Montreal's manager. From 1952 through 1955, Hopper managed the Portland Beavers of the Pacific Coast League, which at the time were unaffiliated with an MLB franchise. He was named the PCL manager of the year in 1953. Hopper managed the Hollywood Stars of the PCL, a Pittsburgh Pirates affiliate, in 1956. He retired from baseball following the season. He ranks #15 of all time in Minor League Wins by a manager. Hopper was posthumously inducted into the International League Hall of Fame in 2009.
