1915: In 1915, the Chamber raised $85,262 to relieve the victims of the appalling Eastland Disaster (a steamer that sank at its dock). That same year, the Foreign Trade Committee could report that its South American office at Buenos Aires had been in existence for five years. The Chamber was the first commercial body to establish a branch office in a foreign city. In this year, the Chamber transferred the office established by the Chamber in Argentina to the Bureau of Foreign and Domestic Commerce of the United States Department of Commerce.

The Civic-Industrial Committee was conducting weekly meetings for young business executives, with attendance averaging more than 300 in 1916.

In 1918, when the government wanted 200,000 tickets sold for the United States War Exposition, the Chamber’s Ways and Means Committee sold 800,000 tickets.

1919 saw the Chamber organize the Mississippi Valley Association and the Chicago Crime Commission. At the end of this year, it also posted its highest membership of 6,365.

In its early years, the Chamber also aided in organizing the Chicago Chapter of the American Red Cross, the Chicago Safety Council, the Chicago Better Business Bureau, the Chicago Plan Commission, and the Advertising Council (Chicago Federated Advertising Club).

1920: The Chamber organized the Citizens Committee to Enforce the Landis Award in 1921. This group broke up a long-standing building tie up and stimulated one of the biggest building booms in the City's history - a boom that continued until 1928. The Chamber brought to Chicago the national headquarters of the Elks.

The Chamber raised $25,000 for Illinois flood sufferers in 1922. It also fought successfully to save the Great Lakes Naval Training Station.

In 1923, the Chamber promoted the organization of the Junior Association of Commerce.

1924 saw the Chamber submit preliminary plans for an underground garage on the lakefront to the South Park Commission.