Paolo Maria Jannacci was born in Milan on September 5, 1972, the only son of the singer-songwriter Enzo Jannacci, who had started out as a jazz pianist in the city's postwar clubs, and Giuliana Orefice. He began music lessons at six, working on instrument and harmony with his father and other teachers, and became a professional musician in 1988. He studied piano at conservatory with Carlo Morena and took jazz piano courses; for jazz itself he names the saxophonist and clarinetist Paolo Tomelleri, who had also taught his father, as his teacher. From 2008 he took advanced courses at the Giuseppe Verdi Conservatory in Como. He has said his father steered him away from a plan to study medicine and toward music.

His first two decades were spent as a working musician in Milan. Italian Wikipedia lists him as a session and solo accordionist for Ornella Vanoni, Cochi e Renato, J-Ax and the group 883, and Discogs credits his accordion on records by 883 (1995), Massimo Ranieri (2001), Roberto Vecchioni (2002) and J-Ax (2011). From 1991 to 2010 he produced many of his father's albums and stage productions, including the 2006 collection The Best. In January 1999 he engineered Marché aux Puces, a jazz album by the drummer Stefano Bagnoli and Enzo Rocco, a name that matters later: Bagnoli became the drummer in his own trio.

His own records began with Notes (2002, Bravo Records), recorded with Bagnoli, the bassist Riccardo Fioravanti and the trumpeter and flugelhorn player Daniele Moretto, who has stayed one of his closest partners. Tape 1 (2004) and My Tangos (2005), a tango-themed record that includes a "Tango for Enzo," followed, along with the soundtrack to the film Mi fido di te (2007), which he scored with Moretto and whose song "Trust in Me" received a Nastro d'argento nomination. The jazz trio record came in 2008. Trio appeared on EmArcy, the Universal jazz imprint, with Marco Ricci on double bass and Bagnoli on drums, fourteen tracks that mix originals such as "Solaris" and "Paradise Lost" with "What Are You Doing the Rest of Your Life" and a Chopin mazurka, and liner notes by the writer Gianni Mura.

Allegra (2013) was released in January 2013. His father passed away in Milan on March 29, 2013, and Jannacci has described the years after it as the point when his group playing tightened, through live work in a "3+1" format. Hard Playing (March 2017) is the result. Recorded in his own home studio with Bagnoli, Ricci and Moretto, it has original themes, two standards ("You Must Believe in Spring" and "Who Can I Turn To?") and a Michel Legrand reworking, and it shipped with a DVD of In concerto con Enzo, the live show of jazz arrangements of his father's songs, on which Tomelleri plays clarinet, Sergio Farina guitar and J-Ax guests on "Desolato." The Milan paper Il Giorno called it perhaps his first genuine jazz record, and he told Avvenire he considered it a clear step up from what came before.

His public profile widened after that through song. Canterò (October 4, 2019, Ala Bianca) was his first album as a singer-songwriter, and its title track took him to the Sanremo Festival in February 2020 with "Voglio parlarti adesso," which finished 16th. The album won the 2020 Targa Tenco for best debut work. He returned to Sanremo in 2024 as a guest of the third night with the writer Stefano Massini, presenting "L'uomo nel lampo," a song about deaths at work, and on the 2026 cover night he joined J-Ax, Cochi e Renato, Paolo Rossi and Ale e Franz for "E la vita, la vita." His newest record, Scimmie ovunque, came out on October 16, 2026 on Ala Bianca Records with Warner/Fuga distribution. Italian press coverage describes it as a pop singer-songwriter album that moves away from the jazz sound of his earlier work, with a duet with Elio of Elio e le Storie Tese.

Jazz has not left his working life. He leads the Paolo Jannacci Band, which has appeared on Italian television programs including Zelig and Che tempo che fa, and plays in a piano trio, a quartet with Ricci, Bagnoli and Moretto, and duos with Moretto and with the guitarist Luca Meneghello. He has performed at Blue Note Milano, teaches ensemble music at the CPM music school in Milan, has written film and documentary scores, has appeared as an actor, and has published two books, in 2011 and 2023.

Jannacci plays in two registers that he keeps mostly apart. In the jazz trio and quartet records he is a lyrical, melody-first pianist whose stated models are Chick Corea, Bill Evans, Herbie Hancock and Oscar Peterson, with a taste for Gershwin and Stravinsky as composers. A reviewer heard an evolution of Evans in his touch, and by his own account Hard Playing moved toward harder harmony, group interplay and a sound near hard bop that brushes against free playing, with a Blue Note-like feel. In the song records, from Canterò onward, the same hands play pop-leaning, theatrical Milanese songwriting, closer to his father's world than to a jazz record, and one reviewer of Canterò called the best moments jazz with pop touches.

The family tie runs through both. Enzo Jannacci was a jazz pianist before he was a songwriter, and Paolo grew up among the players of that Milan scene, including Franco Cerri and Bruno De Filippi. The tribute show In concerto con Enzo carries that repertoire back into a jazz setting. Because the discography divides between jazz, pop and soundtrack work, he sits comfortably in the crossover category: a jazz-trained pianist whose largest public audience came through Sanremo and television rather than jazz clubs, and whose jazz records are modest, melodic and well made.