Giovanni Mirabassi was born in Perugia on 4 May 1970 and has lived in Paris since 1992. He is a pianist whose career runs on two tracks that keep meeting: a working jazz trio and quartet book, and an unusually committed relationship with song, from Léo Ferré and French chanson to the revolutionary and partisan anthems of three continents. His older brother is the clarinetist Gabriele Mirabassi, which matters mainly because the shared surname invites confusion between the two catalogues.

He started at the family piano at the age of two. His father was an amateur musician who played piano, guitar and accordion and sang, and he long discouraged his son from making music a profession. Mirabassi took his first piano lessons at sixteen, from a teacher who introduced him to jazz, and he still describes himself as largely self-taught; the pianist Aldo Ciccolini gave him advice along the way. His own biography names Perugia's jazz festival as the place he first heard the music live, and says he spent his pocket money on records by Thelonious Monk, Miles Davis and Art Blakey. By 1987 he was playing with Chet Baker, and in 1988 with the saxophonist Steve Grossman, according to his Wikipedia and official biographies; neither engagement is documented on a release.

In 1992 he moved to Paris, where he did odd jobs and accompanied singers while he built a place in a city that already had a large Italian jazz community around Paolo Fresu, Flavio Boltro and Stefano Di Battista. In 1996 he won the best-soloist prize at the Tremplin Jazz d'Avignon competition, and the same year formed the duo Dyade with the bassist Pierre-Stéphane Michel. Their album En bonne et due forme (PAN Music, 1996), with Boltro on trumpet and bugle, was his first record.

The trio that followed became his calling card on the French label Sketch. Formed in 1998 with the double bassist Daniele Mencarelli and the drummer Louis Moutin, it made Architectures (1999), on which the guitarist Pierre Durand appears on one track, and the live Dal Vivo! (2001). Between them came the record that changed his profile. Avanti! (Sketch, 2001) is a solo piano album of revolutionary and patriotic songs, among them "Le Chant des partisans", "Hasta siempre", "Le Temps des cerises", "Bella ciao" and "Imagine". The following year he received both a Victoire du Jazz and a Django d'Or as best new talent. In 2003 he recorded (((Air))) for Sketch as a trio with Boltro and the trombonist Glenn Ferris, which the Académie du Jazz named album of the year.

Song kept pulling him out of the trio format. Léo en toute liberté (La Mémoire et la Mer, 2004) is a set of Léo Ferré songs with the singer Nicolas Reggiani, and Cantopiano (Minium/Discograph, 2006) is a solo piano album of French chanson. He has accompanied singers throughout his career, including Agnès Bihl, Mélanie Dahan and, later, Sarah Lancman. Prima o poi (Minium/Discograph, 2005) reunited him with Boltro, Moutin and the bassist Gildas Boclé, with Mirabassi credited as composer.

In 2008 he formed the trio that defined his next decade with the Italian bassist Gianluca Renzi and the American drummer Leon Parker. It recorded Terra Furiosa (Atelier Sawano, 2008), Out of Track (Discograph, 2009) and the live Live @ The Blue Note, Tokyo (2010). In 2009 he began a duo partnership with the saxophonist Stéphane Spira, Spirabassi (Bee Jazz), which returned in 2020 as Improkofiev (Jazzmax) with the drummer Donald Kontomanou, the bassist Steve Wood and the flugelhorn player Yoann Loustalot. ¡Adelante! (Discograph, 2011) is the sequel to Avanti!, recorded in Cuba with Cuban musicians and vocalists, and it opens with "L'Internationale". Tribute to Bill (Star Prod, 2011) is a Bill Evans homage with Renzi and the drummer Eliot Zigmund.

His recordings for C.A.M. Jazz began with Viva V.E.R.D.I. (2013), in which the trio is joined by the Bee String Orchestra under Lorenzo Pagliei and which includes a piece called "Somewhere in Seoul"; No Way Out (2015), a quartet with the vibraphonist Stefon Harris; Live in Germany (2017), solo piano recorded in the auditorium of the Bauer Studios in Ludwigsburg; and Summer's Gone (2018), a trio record with Renzi and the Cuban drummer Lukmil Pérez Herrera.

In 2017 he and the singer Sarah Lancman started Jazz Eleven, an artist-run label for their own records, reissues, vinyl and younger musicians, and it is now his main home. His own releases there include Intermezzo (2019), a set of Italian songs with Lancman and the saxophonist Olivier Bogé as guest; Pensieri Isolati (2021), solo piano; The Swan and the Storm (2022), a new quartet with the tenor saxophonist Guillaume Perret, the bassist Clément Daldosso and Pérez Herrera; Live & Kicking (2024), a duo with the alto saxophonist Rosario Giuliani; and Più Avanti! (2026), a solo piano return to the Avanti! repertoire. Discogs also credits him as producer on releases by the singer Toku and the quartet The Hookup, among others.

Pensieri Isolati was recorded in March 2020, during the first Covid-19 lockdown. It began as an Instagram account where Mirabassi invited people to send him "isolated thoughts" (photos, texts, videos, music), and he wrote and recorded one piece a week in response, with almost no mention of the pandemic itself. In 2022 he made Sound of Love for the Japanese label Venus with a New York trio that includes the bassist Alexander Claffy and the singer Tatiana Eva-Marie, and in 2025 he began a New York trio series of Great American Songbook standards, The N.Y.C Sessions, Vol. 1, with Renzi, the drummer Colin Stranahan and, on two tracks, the guitarist Peter Bernstein. A second thread is Japan: his 2019 album Mitaka Calling interprets music from Studio Ghibli films by Joe Hisaishi, and the release's description says the animator Hayao Miyazaki supplied the jacket illustration.

Away from records, he writes film music, most often for the director Emmanuel Mouret (Caprice, 2015; Mademoiselle de Joncquières, 2018) and for shorts by Gérome Barry, and his official biography records that the French state made him a Chevalier des Arts et des Lettres. Discogs lists 93 distinct releases under his name, 76 of them tagged Jazz. The exceptions are chanson albums and pop sessions with French singers, a sideline to a career built on jazz formats.

Mirabassi names Bill Evans and Enrico Pieranunzi as his main influences, and his own biography adds Charles Mingus for rhythmic approach. Both attributions are his own; no recording credit ties him to Pieranunzi, though he has given the title "Pieranunzi" to tracks on two of his own records, in 1996 and 2009. His playing is lyrical and melody-first, with the tune usually in the right hand, and it leans on a strong rhythmic pulse from the trio underneath.

The repertoire is the more distinctive part. He returns to his own pieces across decades: "28, Rue Manin" is on his first record (1996), on Architectures and on Dal Vivo!; "Behind the White Door" appears on (((Air))) in 2003 and again on Pensieri Isolati in 2021; "Le Chant des partisans" runs from Avanti! through Out of Track to Più Avanti!. He also treats songs as material on equal footing with jazz standards: songs associated with Édith Piaf and Mercedes Sosa sit beside "The Man I Love" on Live in Germany, and Cantopiano and Intermezzo are essentially chanson and Italian-song albums played as piano jazz. His revolutionary-song records are a deliberate political stance rather than a novelty, and the French biography of him calls him an engaged musician.