Rube Foster was owner of the Chicago American Giants and in 1920 created the National Negro League, the first of the Negro Leagues, that lasted until 1931 and ended with the great depression.
Effa Manley
Effa Manley was the only female owner of a Negro League team. Effa co-owned the Newark Eagles along with her husband and was in charge of business. She was a great businesswoman and a generous person. However she expected obedience and for people to do what she asked.
Jackie Robinson
Jackie Robinson is famous for having broke the color barrier in baseball. However breaking the color barrier had a negative effect on the negro leagues. Since all the star players had moved up to major leagues no one wanted to watch negro league games anymore.