A crafty and powerful lefthander pitcher, Cooper is widely considered second only to Bill Foster among Negro League southpaws. He initially made his mark with the Detroit Stars in the ‘20s before being swapped to Kansas City, a deal that brought the Stars five players from the Monarchs roster. He won two-thirds of his decisions with both Detroit and K.C., and helped deliver the Monarchs to the 1929 Negro National League pennant, before going on to manage the Monarchs to three league pennants, 1937-40.