Cockrell began his career as a teenage pitcher and eventually became a Negro National League umpire. During two years for which statistics are available, 1924-25, he won 25 games in leading Hilldale to Negro World Series matchups with the Kansas City Monarchs. He was the winning pitcher in the decisive sixth game in 1925. In the 1930s, Cockrell and Leon Day were Hilldale’s only pitchers in a series of doubleheaders with the Brooklyn Bushwicks, an all-star team of major leaguers organized by Dizzy and Paul Dean. The major leaguers won only one of the 14 games. Cockrell was shot to death in Philadelphia in 1946.