Gary Peacock was born May 12, 1935, in Burley, Idaho. He played a range of instruments before settling on double bass while stationed in Germany during a stint in the Army. By the early 1960s, his imaginative, alert, and elegantly melodic bass playing was heard across the full spectrum of creative jazz in New York, and he became a major figure in the development of avant-garde jazz bass, working with Miles Davis, Bill Evans, Albert Ayler, Don Cherry, Barney Kessel, Jimmy Giuffre, Roland Kirk, George Russell, and pianist Paul Bley, whose own career is covered in full in his JazzProfiles.com profile, as part of Bley's celebrated trio with drummer Paul Motian.

Peacock was probably best known during this early period for Trio '64, his sole 1963 album with Bill Evans. His most enduring association began in 1977, when he was assembled with pianist Keith Jarrett and drummer Jack DeJohnette for his own album Tales of Another (ECM); whose own career is covered in full in his JazzProfiles.com profile. That same trio would go on to become Jarrett's celebrated Standards Trio, touring annually for decades starting with the 1983 ECM releases Standards Vol. 1, Standards Vol. 2, and Changes. ECM Records alone lists Peacock as featured on 51 of its releases.

Peacock died September 4, 2020, in Olivebridge, New York, at age 85.

Peacock's melodic, harmonically adventurous approach to the bass helped redefine the instrument's role within free and avant-garde jazz in the 1960s, and his decades-long partnership with Keith Jarrett and Jack DeJohnette in the Standards Trio became one of the most celebrated and commercially successful piano trios in jazz history.