Led by Rube Foster, owner and manager of the Chicago American Giants, the Negro National League was established on February 13, 1920 by a coalition of team owners at a meeting in a Kansas City YMCA. The new league was the first African-American baseball circuit to achieve stability and last more than one season. At first the league operated mainly in mid-western cities, ranging from Kansas City in the west to Pittsburgh in the east. In 1924 the NNL expanded into the south, adding franchises in Birmingham, Alabama and Memphis, Tennessee.

The Negro American League, was founded in 1937 and including several of the same teams that played in the original NNL, and is known as the western circuit of black baseball. A separate Negro National League was organized in 1933, but eventually became concentrated on the east coast. To distinguish between the two unrelated leagues, they are usually referred to as the first Negro National League (or NNL I) and the second Negro National League (or NNL II).