Cool jazz resulted from the desire of musicians to innovate and to provide an alternative to the complexities of bebop. In the “cool era,” jazz musicians moved jazz closer to classical music and inspired the development of a European classical-oriented jazz form labeled “Third Stream.” This concept, advanced by musician and historian Gunther Schuller, became associated more with white jazz than Black musicians.

Intended for the concert hall rather than the dance hall, cool is characterized by a lyrical melodic shape, softer tonal colors, sparse harmonies, and rhythmic restraint as illustrated in “Autumn in New York,” on the album Django (1956) by Modern Jazz Quartet. Cool jazz ensembles generally consist of three to eight players and often include unexpected instruments such as flute, French horn, oboe, cello, flugelhorn, and vibraphone, heard in recordings by Miles Davis with arranger Gil Evans, such as Miles Ahead (1957), Porgy and Bess (Summertime) (1959), and Sketches of Spain (1960).

Record companies and journalists coined the term “cool,” although musicians of this era disliked any labeling of their music. Nevertheless, the concept of “cool” extended beyond music, referencing a behavior and an attitude widely adopted by artists and intellectuals. Idealized by popular culture of this period, being “cool” became a shield against racial oppression.

Cool jazz placed emphasis on arrangements and compositions rather than complex, improvised solos. The concept of cool in jazz was conveyed by the calm, subdued, soft, or light tonal qualities. The musicians played with little or no vibrato and they favored the middle registers, unlike bebop musicians, who exploited the whole range of the instrument. They no longer only played in 4/4 or 2/4 time; meters such as 3/4, 5/4, and 9/4 became more common. Some composers of the cool era adopted classical European forms such as rondos and fugues.