Kaoru Abe (阿部薫) was born on 3 May 1949 in Kawasaki, the industrial city between Tokyo and Yokohama. His mother, Kikuyo, was the second-eldest sister of the singer Kyu Sakamoto, which made the pop star his uncle. He left Tachibana High School without graduating, taught himself the alto saxophone, and made his debut in 1968 at a Kawasaki jazz spot called Oleo.

The decisive meeting came in 1970, when he began playing with the guitarist Masayuki Takayanagi, a leading figure in Tokyo's free-jazz scene. On 15 March 1970 Abe led a trio at the Pit Inn New Jazz Hall in Shinjuku, playing alto saxophone and shakuhachi. On 28 June, at Koseinenkin Kaikan in Tokyo, he and Takayanagi recorded Kaitai-teki Kohkan (New Direction), a live duo that Sound Creators issued as an LP the same year, with liner notes by the critic Aquirax Aida. On 9 July the two played three sets at Station '70 in Shibuya, which were released decades later as Mass Projection and Gradually Projection. Takayanagi later said that in twenty years of playing jazz he had never met a more frightening musician. Abe was 21.

From 1971 he worked almost entirely alone. The recordings from that stretch map a circuit of university festivals, jazz cafes and tea rooms: Tohoku University in Sendai on 31 October 1971 in a duo with the percussionist Yasukazu Sato, Akita University on 4 December, the jazz spot Basie in Ichinoseki on 6 December, the Pit Inn tea room in Shinjuku on 21 January 1972, Pulcinella in Shibuya in April and July 1972. On 16 December 1972 he recorded a solo set in Osaka that Sound Works pressed in 1974 as 1972 Winter, in an edition of 100 copies. That winter is commonly cited as the high point of his early period. In March 1973 he recorded a double album of unaccompanied alto saxophone for the playwright Masahiko Aku, Partitas, which stayed in the can until 1981. He met the novelist and actress Izumi Suzuki in 1971 and married her in 1973; they had a daughter in 1976 and divorced in 1977.

The most documented year of his life was 1975. In October, the critic Aquirax Aida organised a run of concerts: a duo with the bassist and cellist Motoharu Yoshizawa at Iruma Civic Hall in Saitama on 15 October, a solo set there the next day, and on 18 October a concert at Aoyama Tower Hall in Tokyo titled for Louis-Ferdinand Céline's novel Mort à crédit. The solo material came out in 1976 as the two-LP Mort à Crédit on ALM Records, and the duo recordings as Nord in 1981, the second title taken from another Céline novel. On 12 March 1976 he recorded a studio session at Victor's Big Box Studio in Tokyo, playing alto saxophone, harmonica and piano, which did not appear until 1992.

Between 1976 and 1978 he widened his instrument list and worked the clubs and cafes without a break. At the jazz cafe Passe-Tamps in Fukushima he recorded a long series of sets, some on guitar, harmonica or synthesizer, in 1974 and 1976 and again in November 1977. At Gaya, a club in Hatsudai, Tokyo, he recorded ten volumes of solo sets between September 1977 and August 1978, mostly on alto and sopranino saxophone, and played duos there with the drummer Sabu Toyozumi. On 28 July 1977, at Polydor's 1st Studio in Tokyo, he sat in the front line of Meditation Among Us, a Kitty Records session led by the American drummer Milford Graves, alongside Toshinori Kondo on trumpet, Mototeru Takagi on tenor saxophone and Toshi Tsuchitori on percussion. In 1978 Aida coordinated sessions in Tokyo for the English guitarist Derek Bailey. Abe, Kondo and Yoshizawa played with Bailey at Kavalika in Machida on 3 March, the concert released in 1999 as Aida's Call, and Abe took part in the Polydor session of 19 April that produced Bailey's Duo & Trio Improvisation.

His last months were spent mostly in duo with Toyozumi, at Gaya in February and April, at Raoya in Kichijoji on 5 August and at Goodman in Ogikubo on 13 August. On 28 August, at the club Machikado in Sapporo, he played alto saxophone, guitar and harmonica in what was issued as Last Date 8.28, 1978. The next night, at Dee Dee in Muroran, Hokkaido, an audience member taped a rehearsal and a 14-minute alto improvisation, released as The Last Recording. Kaoru Abe passed away on 9 September 1978 in Nakano, Tokyo, aged 29.

Almost everything he made has reached listeners since. The ALM label put out the Toyozumi duo recordings as Overhang-Party - A Memorial to Kaoru Abe in 1979, and Partitas and Nord followed in 1981. The Nadja edition of Partitas carried sleeve notes from seventeen people, among them the saxophonist Lee Konitz, the saxophonist Frank Lowe, the bassist Sirone, Milford Graves, Ryuichi Sakamoto, Yosuke Yamashita, Toshinori Kondo, the novelists Hiroyuki Itsuki and Ryu Murakami, and the film director Koji Wakamatsu. DIW issued the ten Solo Live at Gaya volumes in 1990 and 1991, P.S.F. Records began its J.I. Collection of solo sets in 1994, and the twelve Live at Passe-Tamps CD-Rs followed in 1999. Youth Inc. issued two large CD boxes in 2012, NoBusiness released the Toyozumi duo Mannyoka in 2018, and Jinya Disc brought out three more documents of the Takayanagi duo and trio in 2020 and 2024. Wakamatsu, who used Abe's music and filmed him playing in a 1978 feature, later directed Endless Waltz (1995), a film about Abe and Suzuki based on Mayumi Inaba's novel, with the writer and punk singer Ko Machida in the lead. A documentary, Abe Kaoru ga Ita, directed by Iggy Cohen, appeared in 2020.

Abe's main instrument was the alto saxophone, and his best-known records are unaccompanied: extended improvisations, many of them running past twenty minutes, with no chord changes to follow. The early work is fast and forceful. By 1976 he was also working on the sopranino saxophone, harmonica, guitar, piano and synthesizer, and the Free Jazz Collective's review of Mannyoka describes the late period as more exploratory and less controlled in tone and articulation than the early work, though it praises the interplay with Toyozumi on that record.

He also played songs. The sets from 1971 onward return to "Lover, Come Back to Me," "Gloomy Sunday," "Blowing in the Wind," "Lonely Woman," "Chim Chim Cheree," "My Foolish Heart" and the Japanese popular song "Akashia no Ame ga Yamu Toki," pulling the melodies apart as he went. They leave recognizable fragments in the middle of otherwise abstract sets.

His relationships with other musicians were brief and intense: Takayanagi in 1970, Yoshizawa in 1974 and 1975, Toyozumi in 1977 and 1978, and Bailey, Graves and Kondo in the last two years. Takayanagi described him as an independent musician who was never carried away by either feeling or intellect alone.