John Aaron Lewis (May 3, 1920 – March 29, 2001) was an American jazz pianist, composer and arranger, best known as the founder and musical director of the Modern Jazz Quartet.

John Lewis was born in La Grange, Illinois, and raised in Albuquerque, New Mexico, and began learning classical music and piano at the age of seven. His family was musical and had a family band that allowed him to play frequently and he also played in a Boy Scout music group. Even though he learned piano by playing the classics, he was exposed to jazz from an early age because his aunt loved to dance and he would listen to the music she played. He attended the University of New Mexico, where he led a small dance band that he formed and double majored in Anthropology and Music. Eventually, he decided not to pursue Anthropology because he was advised that careers from degrees in Anthropology did not pay well. In 1942, Lewis entered the army and played piano alongside Kenny Clarke, who influenced him to move to New York once their service was over. Lewis moved to New York in 1945 to pursue his musical studies at the Manhattan School of Music and eventually graduated with a master’s degree in music in 1953. Although his move to New York turned his musical attention more towards jazz, he still frequently played and listened to classical works and composers such as Chopin, Bach and Beethoven.