Carl Fischer became the preeminent publisher of music for concert band composers such as Percy Grainger and John Philip Sousa, as well as the transcriptions of Erik W. G. Leidzén and Mayhew Lake.

Carl Fischer was also a musical instrument dealer; from the 1890s to 1914 he imported wooden flutes made by Emil Rittershausen (Berlin, Germany).

In 1924, Carl Fischer Music was invited to be a member of ASCAP, adding the company's publications to an established network of artists and composers.

In 1930, National Broadcast Company (NBC) bought Leo Feist, Inc., the largest music publisher of the time, and Carl Fischer, Inc.

Connor became the president of the company and opened Carl Fischer's second retail location, which also housed a concert hall at 165 West 57th Street in midtown Manhattan.

Notable additions to the catalog during the 1950s, 1960s, and 1970s include significant works by Howard Hanson, Norman Dello Joio, Lukas Foss, Peter Mennin, Douglas Moore, and Anton Webern.

It was also during this period that Carl Fischer Music began to publish the works of fast-rising composers such as Henry Brant, Michael Colgrass, Sebastian Currier, Jason Eckardt, Daron Hagen, Lee Hyla, Martin Bresnick, David Carlson, Paul Lansky, Daniel S. Godfrey, Samuel Jones, and David Maslanka.

In 1999, F. Hayden Connor, the great-grandson of founder Carl Fischer, became chairman, and music publishing icon Sandy Feldstein was hired to lead the firm into the 21st century.