Louis Sullivan had a fifteen-year partnership with Dankmar Adler

In June 1875, Sullivan returned to Chicago and completed a brief stint as a draftsman for many companies. One of these assignments was for the recently established company Johnston and Edelmann. The historic meeting between Sullivan and Dankmar Adler, who would become his business partner, was arranged by John Edelmann. At the age of 24, Sullivan joined Adler's office in 1879 and later joined Adler and Sullivan, Architects, as a partner in May 1881. Throughout their 14-year collaboration, more than 100 structures were created, many of which became iconic pieces of American architecture.

Adler's financial acumen, tact with clients, and technical expertise, particularly in acoustics, matched Sullivan's brilliance as a designer. Adler had worked as a draftsman in Chicago after moving there in 1861, and he later returned after fighting in the Civil War. He and Edward Burling established a prosperous partnership in 1871, which they maintained until 1879. The Central Music Hall in Chicago, which was created by independent architect Adler in 1879, served as the model for theaters later created by the team of Adler and Sullivan. Adler was an acoustical consultant who eventually turned to write about the scientific and ethical foundations of design.

Despite doing a lot of domestic work, Adler and Sullivan's art-historical contributions came from their commercial projects. The majority of their structures were located in Chicago, where the 1880s' economic development led to numerous commissions.