Milt Jackson was born January 1, 1923, in Detroit, Michigan, and started as a singer in a gospel quartet before taking up the vibraphone professionally at sixteen. He attended Michigan State University and joined Dizzy Gillespie's sextet in 1945, later working with Gillespie's big band and returning to the sextet from 1950 to 1952, while also freelancing with leading bebop musicians in New York and playing in Woody Herman's band.

Jackson's most significant technical innovation came in the 1940s, when he slowed the motor on his vibraphone's oscillator to roughly a third of the speed Lionel Hampton used, producing a warmer, smokier sound with a vibrato that echoed his own singing voice. He co-founded the Modern Jazz Quartet in 1952, his principal performance vehicle through 1974 and the setting for numerous reunion tours afterward, including annual concert runs starting in 1981 that continued alongside his solo career. He recorded classic sessions with Thelonious Monk ("Evidence," "Criss Cross," "Straight, No Chaser") and with Miles Davis, including "Bags' Groove," which gave him his lifelong nickname.

Jackson died of liver cancer at a Manhattan hospital on October 9, 1999, at age 76.

Jackson's slowed-vibrato technique fundamentally redefined the vibraphone's sound in modern jazz, moving it away from Lionel Hampton's brighter swing-era tone toward a warmer, blues-inflected voice that directly shaped every vibraphonist who followed him, including Bobby Hutcherson and Dave Samuels, both already profiled on this project.