Gunther Schuller stood out as jazz's most steadfast supporter from within the classical sphere. From early on he championed the blending of European classical techniques with jazz improvisation, coining the phrase "third stream" during a 1957 lecture at Brandeis University. Although hybrid experiments had appeared sporadically since 1900, Schuller gave the concept sharper definition and, through partnerships with John Lewis, George Russell, Charles Mingus, and Jimmy Giuffre, fostered fresh third-stream compositions. His own pieces absorbed jazz inflections, yet these elements typically merged more abstractly with his personal 12-tone language than in the works of the jazz artists he supported. On the podium he helped spark the 1970s ragtime revival through vivid renderings of Scott Joplin, while also contributing French horn to landmark jazz sessions. In addition, he tirelessly promoted jazz curricula at universities, an effort that reshaped the music's trajectory from the final decades of the twentieth century onward.
Despite his campaigns to integrate jazz into academic and concert settings, Schuller remained wholly self-taught as a composer. Born to a New York Philharmonic violinist, he received private instruction in theory, flute, and French horn; his rapid command of the latter instrument led to professional engagements with the American Ballet Theatre beginning in 1943, followed by principal-horn posts with the Cincinnati Symphony (1943–1945) and the Metropolitan Opera (1945–1959). He first gained jazz attention by playing French horn on four tracks of Miles Davis's Birth of the Cool sessions in 1950 and later appeared in Gil Evans's orchestra on the trumpeter's Porgy and Bess. During the 1950s his interest in bridging the two worlds prompted him to establish the Jazz and Classical Music Society with John Lewis in 1955, an organization that mounted concerts featuring scores by both classical and jazz composers. One direct result was the Columbia album Music for Brass, which presented pieces by Schuller, Lewis, Giuffre, and J.J. Johnson performed by an ensemble that included Miles Davis, Schuller himself, and New York Philharmonic conductor Dimitri Mitropoulos.
Alongside his celebrated Brandeis lecture, Schuller inaugurated a jazz festival at the university in 1957, commissioning new works from Russell, Mingus, and Giuffre. He continued producing third-stream pieces such as "Transformation" (1957), "Concertino for Jazz Quartet and Orchestra" (1959), "Conversations for the Double Quartet of the Modern Jazz Quartet and Beaux Arts String Quartet" (featured on the MJQ's Third Stream album), and "Variants on a Theme of Thelonious Monk" (1960). With Lewis he also launched the Lenox School of Jazz Summer School and arranged the first jazz concert presented at Tanglewood in 1963.
After relinquishing the French horn in 1962, Schuller concentrated on conducting, composing, teaching, and writing. In 1967 he assumed the presidency of Boston's New England Conservatory of Music, where he immediately created the institution's jazz department—the first to grant a four-year B.A. in the field—and founded the New England Conservatory Jazz Repertory Orchestra and Ragtime Ensemble. He devoted considerable energy to transcribing Duke Ellington and Jelly Roll Morton scores and to preparing authentic performances of Scott Joplin rags. These efforts yielded the 1973 Angel release The Red Back Book, which became a surprise bestseller, revived interest in Joplin's music, and influenced its inclusion in the film The Sting. Schuller's involvement in the ragtime resurgence culminated in 1975 when he led the Houston Grand Opera in the first recording of Joplin's opera Treemonisha for Deutsche Grammophon; he and the NEC Ragtime Ensemble continued touring well into the following decade.
In 1989 Schuller prepared, edited, and conducted the posthumous premiere of Mingus's Epitaph at Lincoln Center, emphasizing that his version did not claim to be definitive. On the classical side, his orchestral work Of Reminiscences and Reflections received the Pulitzer Prize in 1994. He also authored two exhaustive studies, Early Jazz: Its Roots and Musical Development (1968) and The Swing Era: The Development of Jazz 1930–1945 (1989), which examined the idiom with unprecedented analytical depth. In June 2001 the Longy School of Music in Cambridge, Massachusetts, presented him with the Leonard Bernstein Lifetime Achievement Award for the Elevation of Music in Society; weeks later a new Schuller composition received its premiere at the Rockport Chamber Music Festival. During the Boston Symphony Orchestra's 125th-anniversary season in 2009, the ensemble introduced his orchestral score "Where the Word Ends," written when Schuller was 83, and his autobiography Gunther Schuller: A Life in Pursuit of Music and Beauty appeared in 2011. He died in Boston in June 2015 at the age of 89.
