Douglas Melville was the South African backstroke champion in 1946 and held that title at the Transvaal provincial level through 1949. He was most active in water polo, however, and spent over a decade as a member of the Transvaal provincial water polo team. His most notable tournament was the 1952 Summer Olympics, where the team lost its first qualification game against Belgium, won its second against Mexico, and came in third in its preliminary round, losing to Belgium and Spain but winning against Brazil. Melville played as a back in all five matches. By 1956 he was captain of the provincial team, but South Africa did not qualify for the Olympics that year. Out of the water, he was a proficient golfer and was a member of the Kensington Golf Club.