Gil Evans, originally named Gilmore Ian Ernest Green, was born on May 13, 1912, in Toronto, Ontario, Canada. He became one of the most influential jazz composers, arrangers, and bandleaders, renowned for his innovative orchestrations and collaborations with iconic jazz trumpeter Miles Davis. Evans's early life involved frequent relocations across North America due to his stepfather's mining work, which eventually led the family to settle in California. His passion for music was ignited by listening to Duke Ellington, Louis Armstrong, and Fletcher Henderson, and he began studying piano and arranging music at a young age.

In 1933, Evans formed his first jazz big band, Gil Evans & His Orchestra, while attending college. His early career saw him leading bands and arranging music, notably for the Claude Thornhill Orchestra from 1941 to 1948, where he developed a unique instrumentation style that included French horns and tubas. This style became a hallmark of his work and was featured in his arrangements for Miles Davis's "Birth of the Cool" sessions in 1949-50.

Evans's collaboration with Davis in the late 1950s produced seminal albums such as "Miles Ahead" (1957), "Porgy and Bess" (1958), and "Sketches of Spain" (1960), which are considered some of the finest orchestral jazz works of the 20th century. His arrangements were known for their rich textures and harmonic complexity, often challenging the musicians who performed them.

Throughout his career, Evans also worked with a variety of other artists and explored different musical genres, including rock music, which led to collaborations with Jimi Hendrix, David Bowie, and Sting. Despite periods of obscurity, Evans's contributions to jazz were eventually recognized, earning him Grammy Awards in 1960 and 1988.

Gil Evans passed away on March 20, 1988, in Cuernavaca, Mexico, leaving behind a legacy as one of jazz's most important and innovative arrangers.