Benoît Delbecq was born on June 6, 1966, in Saint-Germain-en-Laye, west of Paris, and grew up in nearby Bougival. He began piano at seven with Nicolle Mollard, a former student of Alfred Cortot, and learned jazz harmony from the Paris pianist Jean-Pierre Fouquey. In 1982 he enrolled at the IACP, the school for jazz and improvised music directed by the bassist Alan Silva, and in 1983 he met Mal Waldron, who encouraged him to develop his own music. Alongside the music he studied sound engineering and worked briefly as an assistant director and sound assistant on films. He decided to become a professional musician after the 1987 jazz workshop at the Banff Centre in Canada, where his teachers included Dave Holland, Steve Coleman and Muhal Richard Abrams. He went on to study composition and analysis with Solange Ancona at the Versailles conservatoire, and in 1990 he returned to Banff with the saxophonist Guillaume Orti to work under Coleman. There he met the British drummer Steve Argüelles, who became a long-term partner.

Back in Paris, Delbecq was one of the founders of the Hask collective, which worked from the early 1990s out of the Instants Chavirés venue in Montreuil with Orti, the bassist Hubert Dupont, the saxophonist Stéphane Payen and Argüelles. His quartet recorded Paintings in Marseille in May 1992 for the label Deux Z. He co-led the quartet Kartet, which took the Prix Jeunes Affiches of the Sacem in 1995, and with Argüelles and the guitarist Noël Akchoté he formed The Recyclers, whose Rhymes appeared on Deux Z in 1994. AllMusic also places him in two groups led by the saxophonist Serge Adam, the big band Quoi de Neuf Docteur and Jazz Mic Mac, a project that toured central Africa; the drummer Emile Biayenda, who is on the Jazz Mic Mac record, has been one of his regular partners since.

From 1997 his records for the Canadian label Songlines made him known abroad, beginning with Nancali, a duo with the clarinettist François Houle. Pursuit (2000) introduced his quintet Delbecq 5, Nu-Turn (2003) was his first solo record for the label, and Phonetics (2005) presented the Delbecq Unit. Beside this acoustic work he ran an electronic duo with Argüelles, Ambitronix (We Da Man, 2000, and 9volt Trippin', 2006, both on Plush), and recorded PianoBook (2001) with him. He received a Villa Médicis hors les murs grant in 2001 and a fellowship from the Civitella Foundation in New York in 2009, and in 2009 he founded the label dStream with Argüelles and the sound designer Nicolas Becker.

In 2010 he released two Songlines albums, the solo Circles and Calligrams and the trio record The Sixth Jump with the bassist Jean-Jacques Avenel and Biayenda, and both won a Grand Prix International du Disque from the Académie Charles-Cros. They were preceded by Where Is Pannonica? (2009), a duo of two pianists with Andy Milne, and followed by Crescendo in Duke (2012), his arrangements of music by Duke Ellington for a large cast that includes the clarinettist Tony Coe, the saxophonist Tony Malaby and Antonin-Tri Hoang, and by Fun House (2013), a double-trio session with Fred Hersch in which Gerry Hemingway and Mark Helias are also credited. The same year Delbecq, Hemingway and the trombonist Samuel Blaser recorded Fourth Landscape. A trio with the bassist Miles Perkin and Biayenda made Ink (Clean Feed, 2015), and his quartet with Mark Turner, the bassist John Hébert and Gerald Cleaver made Spots on Stripes (Clean Feed, 2018) and Gentle Ghosts (Jazzdor Series, 2021). He also plays in Illegal Crowns, a quartet with the guitarist Mary Halvorson, the cornetist Taylor Ho Bynum and the drummer Tomas Fujiwara, whose first album appeared on RogueArt in 2016, and he has made duo and trio records with Joëlle Léandre, Marc Ducret and Houle, among others. The Weight of Light (Pyroclastic, 2021) is a solo piano record.

He also writes for the stage, dance and film, has worked with the poet Olivier Cadiot and with actors and directors in Paris, and composed a chamber opera, Patiente 66, with the playwright Dorothée Zumstein, with whom he received the Prix Beaumarchais in 2017. DownBeat's critics named him a rising star on piano in 2018 and 2019. His own website lists him as a lecturer in piano and composition at the Bern University of the Arts (HKB) in Switzerland, where the school also lists him on its staff pages.

Delbecq's signature is the prepared piano: he fits small pieces of wood and rubber between the strings so that hammers and strings behave like a pitched percussion ensemble, and JazzTimes once called him one of the avatars of the prepared piano. Reviewers have compared his percussive, idiosyncratic touch to Cecil Taylor and noted that he treats the body of the piano like a set of tuned drums. His writing is built on superimposed pulses of different speeds, which the critic Philippe Carles called "polyvitesses" in 1994, and he names György Ligeti, Steve Coleman and the music of the Aka people of Central Africa among his sources. He also composes with hand-drawn graphic scores and with proportions taken from language and the visual arts, and in the electronic projects with Argüelles he samples and loops in real time. Among his mentors he counts Mal Waldron, who took him under his wing in the 1980s, and Steve Lacy, who recommended him to Dave Holland for the Banff workshop. AllMusic files him under avant-garde jazz and free improvisation, and the same ear for composed detail and open improvisation runs through his trio, quartet and solo records.