The NNL split the season into two halves. St. Louis won the first half, Chicago won the second half. The teams met at the end of the season in a best-of-9 playoff series to determine the Champion.
The 1928 Chicago American Giants, managed by Dave Malarcher and George Harney, lost the League Pennant after finishing the NNL1 regular season in 4th place with a 55-38-1 record.