Janko Nilović was born on May 20, 1941, in Istanbul, to a Montenegrin father and a Greek mother. As a child he studied piano, oboe and percussion, and in the late 1950s he started his own rock and roll band. He moved to Paris in 1960 and played piano in nightclubs before joining Les Doussis, a trio of Greek musicians in which he played bass, guitar and keyboards; Discogs lists him in that group under the name Yako Doussis. He became a French citizen in 1973. Most of what he has recorded since is library music, written for catalogues that supply recorded music to radio, television and film, and a good deal of it sits in the space between jazz, funk, soul and pop.

In Paris he found work as an arranger and orchestrator for pop singers and television programs while still playing in jazz clubs. In 1967 he and the French-based singer Davy Jones (no relation to the Monkees singer) founded Ju Ju Records, for which he wrote and produced a run of singles; Broc Recordz gathered the 1968 and 1969 output in 2018 as The Definitive Ju Ju Records Collection. His arrangements caught the attention of André Farry, founder of the library label Éditions Montparnasse 2000 (MP 2000), who signed him as a producer. His first LP for the label was Psyc Impressions (1969, MP 06). By his own account on his official site, he chose a jazz-rock style for it, and after hearing the whole record played on Europe 1 radio he stopped arranging for singers and devoted himself to instrumental music.

Psyc Impressions opened the long Impressions series for MP 2000: Vocal Impressions (1971), Pop' Impressions (1972), Supra Pop Impressions (1973) and Soul Impressions (1975), among others. Several used singers and musicians from the cast of Hair, in whose Paris production he worked as an organist. The series also held two straight jazz entries, Jazz Impressions 1 and Jazz Impressions 2 (MP 17 and MP 18, dated 1973 by Wikipedia), instrumental sextet pieces for which he is credited as composer and music director, with André Ceccarelli on drums, trombonist Jacques Bolognesi, tenor saxophonist Bob Garcia, pianist Alain Fougeret and bassist Gilbert Rovère.

His largest jazz project came out first under another name. Giant, issued by Z International Records in 1972 (ZO 201 V), is a jazz-rock big band LP that he arranged and directed, with a band of more than thirty players that included Ceccarelli on drums, saxophonist Jean-Louis Chautemps, Bolognesi, trumpeter Michel Barrot, guitarist Jean-Pierre Alarcen and percussionist Jean Schultheis. By his own telling, the players asked him to start a big band, he wrote the pieces quickly in a jazz-rock style rather than a traditional big band one, and the Hair cast sang on three of them. When only a small number of copies sold, MP 2000 reissued it in 1974 as Rythmes Contemporains (MP 36) in a library sleeve. It is the record hip-hop producers know him for.

In the mid-1970s he began working in Belgium, where he recorded Funky Tramway (1975, Vogue) with the studio group Mad Unity, and he later made Un Homme dans l'Univers (1978, MP 84). Outside his own records he arranged songs for Michel Jonasz and Gérard Lenorman, and his piece "Portrait d'un Robot" was used in a Sesame Street film short of wind-up toys, robots and space shuttles. He left MP 2000 in the late 1970s and set up a music publishing company.

His standing outside France rests on sampling. Producer No I.D. built Jay-Z's "D.O.A. (Death of Auto-Tune)" on "In the Space," a piece from Psyc Impressions; the track is on The Blueprint 3 (2009) and won the Grammy for Best Rap Solo Performance at the 2010 ceremony, with Nilović among its credited writers. Danny! sampled "Tapatapa," from Supra Pop Impressions, for "The Groove," and Dr. Dre used much of "Underground Session," from the Giant and Rythmes Contemporains LP, for "Loose Cannons" on Compton (2015). Labels including Cosmic Sounds, Vadim Music, Dare-Dare, Underdog and Broc Recordz have since reissued his library albums, and he has made new records for Broc: Supra Hip Hop Impressions (2016), Maze of Sounds (2020) with the Soul Surfers, and Cosmos Giants (2024) with JJ Whitefield and Igor Zhukovsky. Wikipedia reported in 2019 that he still worked in Paris.

Nilović describes his own work as illustrative music, written to sit under an image, and the bulk of it is library music rather than jazz: Wikipedia puts his output anywhere from classical, jazz and funk to pop, psychedelia and easy listening, and AllMusic files him under pop/rock and classical rather than jazz. The jazz side is real and documented. It runs from the modal sextet writing of the two Jazz Impressions LPs to the jazz-rock big band of Giant, from the soul-jazz and jazz-funk of Soul Impressions and Chorus to the Belgian funk of Funky Tramway, and the players he hired for it, among them Ceccarelli, Chautemps and Bolognesi, came out of the Paris jazz scene. His sound is built on live drums, fuzz guitar, organ and brass writing, which is why hip-hop producers have mined his records for breaks and hooks, and why collectors of French library records prize the MP 2000 originals. He is best placed as a crossover figure at the point where French jazz musicians, library publishing and later sample culture meet.