The Eastman School of Music owes its origins to the combined vision of two very remarkable men. The first of these was millionaire philanthropist George Eastman (1854–1932), whose vision for his adopted city of Rochester included a strong belief that music could be of immeasurable benefit to the community. The second person was Rush Rhees (1860–1939), who became the third president of the University of Rochester in the year 1900. His leadership during his thirty-five years as president succeeded in transforming what was essentially a small liberal arts college into a modern university. Rhees and Eastman worked together on many civic causes of common interest, and among these was a small but promising music school that had opened in 1913 adjacent to the university campus. The two men believed that the future of music in Rochester depended at least in part on the success of this music school. When its future was in question because of financial concerns, Eastman proposed to purchase the corporate and property rights from the owner and then transfer the ownership to the University of Rochester.

The school in question was known as the D.K.G. Institute of Musical Art. It had been founded in 1913 by Alf Klingenberg and Hermann Dossenbach. In 1914 it acquired a third partner/owner, Oscar Gareissen, but by 1918 both Dossenbach and Gareissen had left the enterprise, leaving Klingenberg as the sole owner. Eastman's purchase of the school in 1918 most likely prevented its demise. The following year the institute was transferred to the University of Rochester, and at about the same time an announcement was made that George Eastman was going to provide the school with magnificent new facilities on the east side of downtown Rochester, about a half-mile from the university's main campus on Prince Street. The new school building, now appropriately known as the Eastman School of Music, opened in September 1921. The adjoining Eastman Theatre opened a year later.

The theater was envisioned by Eastman as being part of his proposal to reach the broadest possible audience by using motion pictures as a vehicle for promoting the enjoyment and appreciation of good music.