Jon Ivar Christensen was born in Oslo on March 20, 1943, the son of a plumber, Ivar Christensen, and his wife Ingrid. He started on piano at home in the mid-1950s, moved to drums, and played in local rock 'n' roll and skiffle bands, but he was largely self-taught and was working in the Gunnar Brostigen big band by the age of fifteen. He also played swing and bop in a quintet led by his cousin, the pianist Finn Melbye, which won the Norwegian amateur jazz championships in 1960, and Christensen took the second soloist prize. In the early 1960s he was in the house band at Oslo's Metropol Jazz Club, where he accompanied visiting Americans including Bud Powell and Dexter Gordon, and he played in Arild Wikstrøm's quartet from 1961 and in pianist Egil Kapstad's trio from 1962 to 1964. A set he played in January 1964 at the Metropol with Kenny Dorham, alongside pianist Tore Sandnæs and bassist Bjørn Pedersen, was later issued on the album Live 1953-56-64.

From 1963 to 1968 he was the drummer in the quartet of the singer Karin Krog, with whom he played the Antibes festival in 1964 and recorded By Myself (1964) and Jazz Moments (1966), the second of them also featuring Jan Garbarek. In 1967 he won the Buddy Prize of the Norwegian Jazz Forum and the readers' poll of the magazine Jazznytt, and he worked that year with the American pianist Steve Kuhn, who was then living in Stockholm, and with the Swedish singer Monica Zetterlund. Two MPS albums from 1968 carry his name: Kuhn's Watch What Happens! and Alto Summit, a date led jointly by Lee Konitz, Pony Poindexter, Phil Woods and Leo Wright. In the same years he joined the circle around the American composer and theorist George Russell, who was living in Scandinavia, and played alongside Garbarek on several of Russell's recordings, among them The Esoteric Circle and Electronic Sonata for Souls Loved by Nature (both released in 1971) and a 1970 appearance at the Berlin Jazz Festival.

His international career grew out of Garbarek's quartet. With guitarist Terje Rypdal and bassist Arild Andersen behind the saxophonist, Christensen recorded Afric Pepperbird in September 1970, one of the first albums on the new German label ECM, and he followed it with Garbarek's Sart (recorded April 14 and 15, 1971), Rypdal's ECM debut (August 1971), and Underwear, a trio record with pianist Bobo Stenson and Andersen made at Oslo's Arne Bendiksen Studio on May 18 and 19, 1971. ECM's founder and producer Manfred Eicher came to rely on him so heavily that obituaries called him the label's house drummer. In November 1973 he recorded Witchi-Tai-To with the Garbarek-Stenson quartet and the bassist Palle Danielsson. Keith Jarrett then took Garbarek, Danielsson and Christensen as his European Quartet: its first album, Belonging (April 1974), gave the band its nickname, and the group recorded five ECM albums between 1974 and 1979: Belonging, My Song, Personal Mountains, Nude Ants and Sleeper. In between he recorded Ralph Towner's Solstice in December 1974 with Garbarek and the bassist Eberhard Weber, Weber's own Yellow Fields in September 1975 with Charlie Mariano and Rainer Brüninghaus, and Enrico Rava's The Pilgrim and the Stars in 1975. The European Jazz Federation named him drummer of the year in 1975.

His only album under his own name, No Time for Time, was recorded in 1976 with a second drummer, Pål Thowsen, plus Rypdal and Andersen, issued on the Zarepta label in early 1977, and honored with the 1977 Spellemannprisen, the Norwegian record industry's award. In 1983 he and Andersen formed the quintet that became Masqualero, with trumpeter Nils Petter Molvær, saxophonist Tore Brunborg and keyboardist Jon Balke; guitarist Frode Alnæs replaced Balke on Aero (1988), and the group was a quartet on its last record, Re-Enter (1991). Masqualero made four albums, three of them Spellemann winners (1983, 1986 and 1991). Outside the band he kept up the ECM work: Jan Garbarek's Photo with Blue Sky, White Cloud, Wires, Windows and a Red Roof (recorded December 1978) and Paths, Prints (December 1981, with Bill Frisell), Miroslav Vitouš's group, Rainer Brüninghaus's Freigeweht, John Abercrombie's Animato and Charles Lloyd's Fish Out of Water (both 1990). He received the Gammleng Prize in 1984 and the Oslo City Art Prize in 1987, and in 1988 he married the actress and director Ellen Horn, who later served as Norway's minister of culture.

In the 1990s he made records with Knut Riisnæs and John Scofield (the 1992 album credited to Riisnæs and Christensen, which also won a Spellemannprisen), with Anouar Brahem (Khomsa, 1995), with Stenson's trio (Reflections, recorded in 1993 and issued in 1996, then War Orphans and Serenity), and with the group of Lars Danielsson, Dave Liebman and Stenson, which recorded live at Visiones in New York on March 8 and 9, 1996. In February 1997 he joined Tomasz Stańko's septet for Litania, an ECM album of music by Krzysztof Komeda. ECM issued a retrospective, Selected Recordings, in 2004. In his last years he worked with a younger Danish generation: guitarist Jakob Bro's Gefion (recorded November 2013, released 2015), with Thomas Morgan on bass, and Bro's Returnings (recorded July 2016, released 2018), which Jazz Journal's obituary describes as his last ECM session, as well as a piano trio with Carsten Dahl and Andersen. Oslo Jazzfestival gave him its Ella Prize in 2018, the year he played the Aarhus Jazz Festival with Bro, trumpeter Palle Mikkelborg and Morgan. The same obituary names pianist Yelena Eckemoff's Nocturnal Animals, recorded in April 2018, as his final recording. Jon Christensen passed away in Oslo on February 18, 2020, at the age of 76. He was survived by his wife Ellen Horn and his daughters Emilie Stoesen Christensen, a singer and actress, and Jannicke Dahr.

Christensen was a drummer of space and suggestion more than of timekeeping. German Wikipedia calls him one of the first and foremost European exponents of what it terms "broken swing," and he himself described his sense of rhythm as a wave rather than a strictly linear pulse, a view he extended in a 2005 Modern Drummer interview to the claim that tempo is more than metronomic time. His 22-inch Istanbul K ride cymbal, dry and bright, became closely tied to the sound of ECM in the 1970s, and he moved easily between brittle, clattering figures and airy, diffuse textures, as comfortable behind Keith Jarrett's long-form improvisations as in the free-leaning quartets of Jan Garbarek and Terje Rypdal. Raised on swing and bop and schooled by accompanying American visitors such as Dexter Gordon and Bud Powell in Oslo, he went on to help define the quieter, more open sound of Nordic jazz. The opening drum passage of "Piscean Dance" on Solstice was sampled by the American hip hop group Atmosphere on "Shoes" (2003). Obituaries described him as one of the great drummers of modern jazz and improvisation, and Masqualero is cited as an early distillation of the Nordic jazz style and as an influence on later players such as pianist Tord Gustavsen.