It played its first concert on October 16, 1891 conducted by Theodore Thomas, making it the third oldest symphony orchestra in the United States (behind the New York Philharmonic and the Saint Louis Symphony Orchestra). At that time it was known simply as the Chicago Orchestra, before changing its name to the Theodore Thomas Orchestra in 1906, and taking its present name in 1912. Theodore Thomas is still honored in the name of the orchestra's home auditorium, the Theodore Thomas Orchestra Hall.
In 1905, Frederick Stock became principal conductor, a post he held until 1942. Other principal orchestras have been Désiré Defauw (1943-47), Artur Rodzinski (1947-48), Rafael Kubelik (1950-53), Fritz Reiner (1953-63), Jean Martinon (1963-69), Georg Solti (1969-91) and, from 1991, Daniel Barenboim.
The orchestra has also had a number of distinguished guest conductors. Since 1995, Pierre Boulez has been Principal Guest Conductor.