Milton (Milt) Jackson (January 1, 1923 - October 9, 1999) was an American jazz vibraphonist and one of the most important figures in the hard bop style, although he performed in several subgenres of jazz. A very expressive player, Jackson differentiated himself from other vibraphonists in his attention to variations on harmonics and rhythm. He was particularly fond of the 12-bar blues at slow tempos. He preferred to set the vibraphone's oscillator to a low 3.3 revolutions per second (as opposed to Lionel Hampton's speed of 10 revolutions per second) for a more subtle vibrato. On occasion, Jackson would also sing and play piano professionally.
He was discovered by Dizzy Gillespie, who hired him for his sextet in 1946. He quickly acquired experience working with the most important figures in jazz of the era, including Woody Herman, Howard McGhee, Thelonious Monk, and Charlie Parker.
In the Gillespie big band one of his jobs was to play in a quartet with John Lewis, Percy Heath, and Kenny Clarke while the horn section took a break from the demanding high-register horn parts. This group, known from around 1950 as the Milt Jackson Quartet, eventually became the Modern Jazz Quartet (MJQ) by around 1952, and had a long independent career of some 20 years until disbanding in 1974 when Jackson split with Lewis in an attempt to make more money on his own (though it reformed in 1981 and last recorded in 1993). Jackson then toured alone, performing in various small combos.