[4] As an officer of the Aero Club of Illinois, founded on February 10, 1910, McCormick became the third president in 1912, following Octave Chanute and James E.

However, Chicago's irregular weather, especially the crosswinds, made a shamble of schedules, and the airline disappeared before the end of the year.

"[7][8] McCormick became chairman of the board of International Harvester Company in 1935, replacing his older brother Cyrus Jr.

He and Edith resided at 1000 Lake Shore Drive in Chicago and were the parents of five children before their divorce in December 1921: After his divorce from Edith, and before his second marriage, McCormick sought to fortify himself by undergoing an operation by Serge Voronoff, a surgeon who specialized in transplanting animal glands into aging men with impotency.

Orson Welles claimed that McCormick's lavish promotion of Walska's opera career—despite her renown as a terrible singer—was a direct influence on the screenplay for Citizen Kane, wherein the titular character does much the same for his second wife.