The entry of the United States into World War I drained all four teams by drafting players into the military, with St. Leo’s affected the most.
In 1926, the SLSL briefly expanded to include Chicago Sparta, but the team did not complete the season and withdrew on November 11, 1926.
The league, which had experienced considerable internal strife, including lawsuits between teams over player tampering, had finally collapsed.
The only opportunities for teams from one region to test themselves against the best on a national level came from ad hoc cups and off-season tours.
In 1913, the St. Louis Soccer League came to national attention when St. Leo’s tied the Paterson True Blues, winners of the American Cup.