Harold Mabern Jr. (March 20, 1936 – September 17, 2019) was an American jazz pianist and composer, principally in the hard bop, post-bop, and soul jazz fields. He is described in The Penguin Guide to Jazz Recordings as “one of the great post-bop pianists”.

Mabern was born in Memphis, Tennessee on March 20, 1936. He initially started learning drums before switching to learning piano. He had access to a piano from his teens, after his father, who worked in a lumber yard, saved to buy him one. Mabern learned by watching and emulating pianists Charles Thomas and Phineas Newborn Jr. 

Mabern moved to New York City in 1959. According to his own account, he moved there with saxophonist Frank Strozier on November 21, 1959, checked in at a hotel and then went to Birdland, where he met Cannonball Adderley, who asked him if he wanted a gig. Mabern accepted and was shown inside, where trumpeter Harry “Sweets” Edison, who was looking for a pianist to replace the soon-to-depart Tommy Flanagan, auditioned him and offered him the place. A few weeks later, most of the members of this band then joined Jimmy Forrest for a recording in Chicago that resulted in the albums All the Gin Is Gone and Black Forrest, which were also guitarist Grant Green debut recordings.

Mabern steadily built a reputation in New York as a sideman, playing with, among others, Lionel Hampton‘s big band in 1960 (including a tour of Europe), the Jazztet for 18 months in the period 1961–62, accompanying vocalists, including Betty Carter, Johnny Hartman and Arthur Prysock, and working with trumpeter Donald Byrd and drummer Roy Haynes. After completing a 1963 tour with Haynes, he had a six-week engagement at the Black Hawk in San Francisco with Miles Davis.