John Birks "Dizzy" Gillespie was born October 21, 1917, in Cheraw, South Carolina, the youngest of nine children of James Gillespie, a bricklayer who led a local band on weekends and kept instruments in the house, and Lottie Gillespie. His father died when Gillespie was ten. He began teaching himself piano at four, picked up trombone and then trumpet by twelve, and won a scholarship to the Laurinburg Institute in North Carolina, where he studied for two years before the family moved to Philadelphia in 1935. His first professional work came that year with the Frank Fairfax Orchestra, followed by a stint in Edgar Hayes's band; in May 1937 he replaced Frankie Newton in trumpeter Teddy Hill's orchestra, making his first recording ("King Porter Stomp") that August. In 1939 dancer Lorraine Willis, whom he had met in Washington, D.C., helped him land a chair in Cab Calloway's prominent orchestra, where he sat in the trumpet section alongside players Calloway would later call some of the best he ever employed. The association ended badly in late 1941: after a backstage spitball incident during a Hartford, Connecticut show, an angry confrontation escalated and Gillespie stabbed Calloway in the leg; Calloway fired him on the spot. Gillespie married Lorraine on May 9, 1940, in Boston, and the marriage lasted the rest of his life.

Freelancing through the early 1940s, Gillespie wrote big-band arrangements for Woody Herman and Jimmy Dorsey and worked briefly with Charlie Barnet and Benny Carter. In 1943 he joined pianist Earl Hines's band, later described as "the incubator of bop," where he first worked alongside alto saxophonist Charlie Parker; the two reunited the following year in vocalist Billy Eckstine's band, a proving ground for the emerging modern-jazz style. Gillespie left big bands in 1944 to concentrate on small combos, playing alongside Parker at Harlem's Minton's Playhouse and Monroe's Uptown House, where a loose community of musicians was working out bebop's harmonic and rhythmic vocabulary in after-hours jam sessions. On February 16, 1944, he took part in "Woody 'n' You," a session led by Coleman Hawkins for Apollo Records often cited as the first formal bebop recording, and on May 11, 1945, he and Parker cut "Shaw 'Nuff" and "Lover Man" for the tiny Guild label (Guild 1002) with Al Haig, Curly Russell, and Sidney Catlett, among the definitive early documents of the new music. A June 22, 1945, concert at New York's Town Hall introduced bebop to a wider audience, and Gillespie began organizing his own big bands later that year; a December 1945 residency with a sextet featuring Parker at Billy Berg's club in Los Angeles met a mixed reception from an audience unprepared for the style, and the group broke up shortly after. Signing with RCA Victor's Bluebird subsidiary in February 1946, Gillespie built a full big band that, with arrangements from Tadd Dameron, Gil Fuller, and George Russell, became one of the most advanced ensembles in jazz.

In 1947, bandleader and fellow trumpeter Mario Bauzá introduced Gillespie to Cuban conga player and singer Chano Pozo, and the pairing opened a second major chapter in Gillespie's career. Pozo joined Gillespie's orchestra and co-wrote "Manteca" and "Tin Tin Deo" with him; "Manteca," recorded for RCA Victor on December 30, 1947 (released as RCA Victor 20-3023, backed with "Cool Breeze"), fused big-band bebop with Afro-Cuban rhythm and became one of the most influential recordings in the merger of the two traditions. Gillespie also commissioned George Russell's "Cubano Be, Cubano Bop," featuring Pozo, cementing his and Bauzá's role as pioneers of what came to be called Afro-Cuban or Latin jazz. Pozo was shot and killed in a Harlem bar in December 1948, only a year into the collaboration. Gillespie's late-1940s big band, whose sides for RCA Victor between 1937 and 1949 were later collected on the 1995 compilation The Complete RCA Victor Recordings, broke up in 1950 amid the declining economics of big-band touring, though he continued leading orchestras intermittently through the 1950s. On June 6, 1950, Gillespie reunited in the studio with Parker, pianist Thelonious Monk, bassist Curly Russell, and drummer Buddy Rich for the session issued in 1952 as Bird and Diz (Clef/Mercury MGC-512), the only record to feature Parker, Gillespie, and Monk together, and one of their last studio meetings. A more informal reunion followed on May 15, 1953, when Gillespie, Parker, Monk's fellow pianist Bud Powell, bassist Charles Mingus, and drummer Max Roach played a single Toronto concert, released on Mingus's own Debut label as Jazz at Massey Hall, billed only as "The Quintet" because Parker, under contract elsewhere, was credited as "Charlie Chan."

Through the mid-to-late 1950s Gillespie led a series of acclaimed big bands and small groups, cementing a stage persona built around a beret, horn-rimmed glasses, balloon cheeks when he played, and comic scat singing that made him one of jazz's most recognizable public figures. His trumpet's signature upturned bell dates to January 6, 1953, when dancers Stump and Stumpy accidentally knocked his horn off its stand at a party for Lorraine's birthday, bending the bell 45 degrees; Gillespie liked the altered sound and had the Martin Band Instrument Company build him a custom horn to the same angle. In 1956 the U.S. State Department sponsored a Gillespie big band's tour of the Middle East and Latin America, earning him the nickname "the Ambassador of Jazz" and yielding the album World Statesman (Norgran, 1956), with a band that included Quincy Jones, Melba Liston, and Phil Woods. His later 1950s Verve output includes Dizzy Gillespie at Newport (1957), For Musicians Only (1957, with Stan Getz and Sonny Stitt), Birks' Works (1958), and Sonny Side Up (1959, pairing tenor saxophonists Sonny Rollins and Sonny Stitt). His early-1950s septet and octet also gave a young John Coltrane some of his first recorded solos; Coltrane played alto and then tenor in Gillespie's band from the fall of 1949 into the spring of 1951, taking his first documented recorded solo on "We Love to Boogie" on March 1, 1951. Gillespie continued exploring orchestral settings into the 1960s, commissioning Lalo Schifrin's Gillespiana suite (1960) and J.J. Johnson's Perceptions (1961), and recording A Portrait of Duke Ellington (1960) and Something Old, Something New (1963, Philips), the latter featuring his signature original "Con Alma."

Gillespie remained a prolific recording and touring artist into his final years, much of it for Norman Granz's Pablo label, including Dizzy Gillespie's Big 4 (1975, with Joe Pass and Ray Brown), the electric, Schifrin-arranged Free Ride (1977), and Digital at Montreux, 1980 (1981, with Toots Thielemans). Politically outspoken throughout his career, he ran a mock write-in campaign for U.S. president in 1964, proposing a cabinet that included Duke Ellington, Miles Davis, Max Roach, and Thelonious Monk, with comedian Phyllis Diller as his running mate, donating proceeds from campaign merchandise to civil rights organizations. He converted to the Baháʼí Faith in 1968 following the assassination of Martin Luther King Jr. In the 1980s he formed the United Nation Orchestra, a large ensemble built to showcase Latin, Caribbean, and American jazz musicians together; a concert filmed June 10, 1989, at London's Royal Festival Hall was released as Live at the Royal Festival Hall (Enja, 1990) and won the 1991 Grammy Award for Best Large Jazz Ensemble Album, one of Gillespie's last major performances. He was diagnosed with pancreatic cancer in 1991, led his final recording session in January 1992, and gave his last public performance that February in Seattle. Dizzy Gillespie passed away on January 6, 1993, in Englewood, New Jersey, at age 75; singer Roberta Flack performed "Amazing Grace" at his funeral, and he was buried in an unmarked grave at Flushing Cemetery, Queens.

Where Louis Armstrong and Roy Eldridge, Gillespie's own early idol, had defined the trumpet's role in swing-era jazz through melodic drive and range, Gillespie pushed the instrument into bebop's harmonically dense, rhythmically unpredictable new language, developing an instantly identifiable style built on wide interval leaps, dazzling double-time runs, and a sly, playful sense of harmonic substitution that could turn a familiar standard's chord changes inside out. Alongside Charlie Parker, he is credited as bebop's co-founder, and critics of the era dubbed his unpredictable, exploratory phrasing "the sound of surprise." His second major legacy, developed with Cuban musicians Mario Bauzá and Chano Pozo, was Afro-Cuban jazz: fusing bebop's harmonic sophistication with Cuban clave rhythm on records like "Manteca" and Afro, he opened a pathway that generations of Latin jazz musicians followed. Gillespie was also a gifted composer and bandleader whose original tunes, among them "A Night in Tunisia," "Groovin' High," "Salt Peanuts," and "Con Alma," became jazz standards, and a natural showman whose beret, glasses, bent trumpet, and scat vocals made him one of jazz's most publicly recognizable figures without ever undercutting the seriousness of his musicianship. He mentored or profoundly influenced generations of trumpeters, including Miles Davis, Fats Navarro, Clifford Brown, Freddie Hubbard, Jon Faddis, Arturo Sandoval, and Wynton Marsalis, and received a Grammy Lifetime Achievement Award (1989), Kennedy Center Honors (1990), and NEA Jazz Master recognition among numerous other honors.