John Josephus Hicks Jr. was born in Atlanta on December 21, 1941, the eldest of five children of the Rev. John Hicks Sr. and his wife Pollie. Both parents held university degrees, and Hicks described the household as middle-class and expectant: "I was brought up as a decent human being, where you had aspirations and there were expectations." His father's rising posts in the Methodist church moved the family from city to city. In Los Angeles his mother started him at the piano when he was about seven; organ lessons and church choirs followed, along with brief attempts at the violin and the trombone. By eleven he could read well enough to play in his father's services. His father also made sure the boy met Duke Ellington and heard the Count Basie and Jimmie Lunceford orchestras in person.

The family settled in St. Louis when Hicks was fourteen, and that is where the piano stopped competing with anything else. At Sumner High School his classmates included the trumpeter Lester Bowie, in whose band the Continentals he played; he began sitting in with the city's older musicians, and named the local pianist John Chapman as an early model. His listening ran from Fats Waller to Thelonious Monk by way of Methodist hymnody, and he gravitated early to Horace Silver's blues-rooted writing. When Eddie "Lockjaw" Davis and Johnny Griffin came through town without a pianist he was pushed onto the stand and held his own. Summers he spent on the road across the South with the blues singers Little Milton and Albert King, sometimes playing four jobs in eighteen hours. His first professional work, with Little Milton in 1958, doubled as an ear-training course: the house piano was so badly out of tune that he had to transpose every number. He took a course at Lincoln University in Chester County, Pennsylvania, where he roomed with the drummer Ronald Shannon Jackson, and spent a short time at the Berklee School of Music in Boston.

At Clark Terry's urging he moved to New York in 1963. The Guardian's obituary has him hired within hours of arriving by the blues singer Big Maybelle; The New York Times gives his first New York job as accompanying the singer Della Reese. Either way the work came fast: Joe Farrell's group, a road tour with the ex-Basie men Al Grey and Billy Mitchell, an appearance on CBC Television behind Jimmy Witherspoon, and a place in Pharoah Sanders's first band. Then Cedar Walton recommended him to Art Blakey, and in 1964 Hicks took the piano chair in the Jazz Messengers. His recording debut came that November on 'S Make It, with Lee Morgan, John Gilmore and Curtis Fuller in the front line, and early in 1965 he toured Japan, France, Switzerland and England with the band. Blakey pressed his sidemen to write, and locked the parts in his drum case after a single run-through. Hicks stayed two years. He then worked on and off with Betty Carter from 1965 to 1967, whose taste for extreme slow tempos he credited with rebuilding his sense of time, and spent 1968 to 1970 in Woody Herman's big band, writing arrangements as well as playing. He taught jazz history and improvisation at Southern Illinois University from 1972 to 1973.

The 1970s pulled him toward the music's open edge without ever detaching him from its center. He recorded with Oliver Lake, played and recorded in the Netherlands with Charles Tolliver's Music Inc, and appeared on Lester Bowie's Fast Last! alongside Julius Hemphill and Joseph Bowie. His own first session as a leader was cut in London on May 21, 1975 and yielded two albums, the trio Hells Bells and the solo Steadfast, both of which Strata-East held back until 1980. That same year he rejoined Betty Carter, and the five years that followed did more for his name than anything before them; The Audience with Betty Carter, recorded live in San Francisco in December 1979, is the record most listeners met him on. Carter dismissed him in 1980 over his drinking, but by then he was launched. Some Other Time (Theresa, 1981), a trio with Walter Booker and Idris Muhammad, put his composing on record, including "Naima's Love Song," written for his daughter and the piece that follows him everywhere.

From then until his death he was one of the most heavily recorded pianists in American jazz, credited on close to 400 releases and leading more than thirty of them. He held long chairs with three saxophonists at once: Arthur Blythe, on whose Columbia albums Illusions (1980) and Blythe Spirit (1981) he plays the acoustic-band tracks against James Blood Ulmer's electric ones; David Murray, across a dozen records from Morning Song (Black Saint, 1984) onward; and Pharoah Sanders, from Rejoice (1981) through the Frankfurt duo concert of February 1986 that went unreleased for thirty-seven years. From 1983 the flutist Elise Wood was a regular member of his groups; the two formed a company, John Hicks-Elise Wood, Inc., toured the United States, Europe and Japan, and married in June 2001. He led a quartet with Sonny Fortune, Walter Booker and Jimmy Cobb, assembled a big band in the autumn of 1982 and revived it from time to time, and played with the Mingus Dynasty and the Mingus Big Band, including the 1989 performances of Epitaph under Gunther Schuller. Working trios followed one after another: the New York Unit with Richard Davis and Tatsuya Nakamura for Japanese labels, the New York Rhythm Machine with Marcus McLaurine and Victor Lewis, the Keystone Trio with George Mraz and Idris Muhammad for Milestone, and from 1997 the HighNote group with Dwayne Dolphin and Cecil Brooks III.

That last band made the records he sold most of. Between 1997 and 2003 Hicks cut five HighNote songbook albums devoted to composer-pianists, four of them tied to Pittsburgh: Something to Live For (Billy Strayhorn), Nightwind (Erroll Garner), Impressions of Mary Lou (Mary Lou Williams), Music in the Key of Clark (Sonny Clark) and Fatha's Day (Earl Hines). He was called the label's house pianist, and played on five of David "Fathead" Newman's HighNote albums as well. He joined Joe Lovano's quartet in 1998 and his nonet the year after. In his last decade he taught at New York University and The New School, and told an interviewer in January 2006, "I don't care how advanced my students are, I always start them off with the blues. It all comes from there." Early that year he played in a big band led by Charles Tolliver and toured Israel with a Monk program. His final studio date, On the Wings of an Eagle, was recorded for Chesky on March 10, 2006 with Buster Williams and Louis Hayes; he had a Polish tour with Eddie Henderson in the book. His last performance was at St. Mark's United Methodist Church on 118th Street, his late father's church, the Sunday before he passed away from internal bleeding on May 10, 2006, aged 64. He is buried at South-View Cemetery in Atlanta, and his papers, scores and recordings are held by Duke University.

Hicks was hired for drive. Fellow pianist George Cables compared his energy and his interval choices to McCoy Tyner's and called him "a very strong and energetic player, and a very warm player, very much part of the tradition"; The Guardian's John Fordham singled out his "alacrity of thought and execution"; Betty Carter, who heard more of him than most, said simply that nobody sounded like him and that the energy was always there. What made him a first call across such different bandstands, from Woody Herman's big band to Arthur Blythe's electric quartets, was that the drive never came at the cost of the song. The Penguin Guide to Jazz, answering the charge that his playing could seem insubstantial, argued the opposite: he was more concerned to work inside a tune's dimensions than to leave them behind. Reviewers kept returning to two things, the shading in his left hand and a "reverence for melody" that gave his improvising a destination, and to the way he could shape a chord so that it rose and fell like a breath. Behind all of it sat the church organ, the blues jobs with Little Milton and Albert King, and a stated line of descent running from Fats Waller through Thelonious Monk. As a writer he tailored parts to particular players, which is why his sextet and quintet charts read as portraits of the people on them, and his best-known tune, "Naima's Love Song," has outlived most of the records it appears on.