Paolo Tomelleri was born in Vicenza on June 13, 1938, and moved to Milan, where he studied clarinet at the Giuseppe Verdi Conservatory, earning his diploma in 1957. He had already begun playing jazz a year earlier, joining the trad-jazz group the Windy City Stompers in 1956. In 1959 he joined I Cavalieri, a Milan-based group whose lineup also included pianist Enzo Jannacci and saxophonist Luigi Tenco, recording for the Dischi Ricordi label. Discogs credits Tomelleri on well over 100 releases under his own name and various group billings, spanning more than six decades, and he remains professionally active as of this profile.

Tomelleri's longest single professional relationship grew out of that circle: he served as saxophonist and clarinetist for Enzo Jannacci for more than thirty years, arranging and recording with him into the 1990s. From 1960 he also worked as a saxophonist and arranger for Giorgio Gaber and Adriano Celentano, and his session and arranging credits run through Italian popular music for two more decades, with Discogs-confirmed studio appearances behind Nilla Pizzi in the 1960s and, across the 1970s onward, Iva Zanicchi, Giorgio Gaber, Alvaro Amici, Gigliola Cinquetti, and, as recently as 2025, Marcella Bella. That side of his career put him on the podium at the Sanremo Festival more than once: in 1971 he conducted one of the festival orchestras behind Adriano Celentano, and in 1973 he did so again, the same year he was credited as composer of "Sugli Sugli Bane Bane," performed at Sanremo by the vocal group Le Figlie del Vento. His own early leader records from this period, including the LPs Paolo Tomelleri (1972, Luna Park) and Sax Magico Con Paolo Tomelleri and Ma Quel Giorno (both 1973, Kansas), are billed to the Orchestra Paolo Tomelleri and are tagged on Discogs as easy-listening, funk/soul and pop instrumental records rather than jazz.

Running alongside the pop-session catalog, Tomelleri built a parallel career inside Milan's postwar trad-jazz and swing revival scene, much of it centered on guitarist Lino Patruno's Milan College Jazz Society, the house rhythm section Patruno used to back touring and resident American jazz musicians. Discogs credits Tomelleri on tenor saxophone on Billy Butterfield Plays George Gershwin (1978, Carosello), an all-Gershwin session with the American trumpeter Billy Butterfield, and on clarinet and alto saxophone on Patruno's Old America (recorded 1986, reissued 1990), a Louis Armstrong-repertoire record also featuring pianist Romano Mussolini. He is also billed, via the Orchestra Paolo Tomelleri and Joe Venuti Quintet group entities on Discogs, on Italian recordings and appearances backing the American violinist Joe Venuti. On the 1997 Musica Jazz compilation Caprice, credited to drummer Gil Cuppini, Tomelleri plays alto saxophone alongside Venuti on the tracks "Caravan" and "Sweet Georgia Brown," a genuine same-track studio pairing rather than a shared billing alone. Biographical sources also describe collaborations with clarinetist Tony Scott and, in his later jazz-festival years, with Clark Terry, Phil Woods, Bill Coleman and Wild Bill Davison; none of these is independently confirmed at the Discogs credit level, so they are stated here as biography-only claims.

In 2022 Tomelleri was one of twelve veterans of Milan's Santa Tecla club, including Enrico Intra, Franco Cerri and Guido Manusardi, each contributing a separate track to the various-artists tribute LP Santa Tecla Io C'ero (MAP Jazz), produced by Codiceicona and edited by Intra and Massimo Monti; the credited musicians do not necessarily perform together on the release, and the album functions as a joint tribute rather than a group session. Tomelleri's own leader catalog turns more consistently toward jazz from the early 1990s: Mister Clarinet (1991, Ariston), an album of original compositions; Milan Swing (1993, L+R Records), a quintet session with bassist Marco Ratti, drummer Stefano Bagnoli, pianist Carlo Uboldi and the German vibraphonist Fritz Hartschuh; From Duo to Big Band (1996, Giants of Jazz); Unforgettable (1999, Giants of Jazz); Any Old Time (2010, Alessio Brocca Edizioni Musicali); and A King, A Queen & Four Jacks (2017, same label), a quintet date with singer Irene Natale, pianist Fabrizio Bernasconi, guitarist Luciano Zadro, bassist Marco Mastrangelo and drummer Tony Arco. A separate 2018 record, Le Canzoni del Signor Dario Fo, made with singer Giangilberto Monti, sets Dario Fo's songs and is tagged Pop rather than Jazz on Discogs.

Since 1993 Tomelleri has directed his own 20-piece Paolo Tomelleri Big Band, playing arrangements drawn from Fletcher Henderson, Benny Goodman, Artie Shaw, Duke Ellington and Count Basie. He also currently leads three smaller ensembles: Paolo Tomelleri's Jazz Devils, a dixieland group; a swing quartet built as a tribute to Benny Goodman; and We Bop, a bebop group. He teaches jazz clarinet, jazz saxophone and ensemble, and directs the Swing Band, at Milan's Civica Scuola di Musica Claudio Abbado, and for several years was the house clarinetist at Milan's Capolinea jazz club. Beyond performing and teaching, he has composed music for film, theater, documentaries and advertising, and has published instructional books on harmony, solfege and clarinet study.

Tomelleri's musical identity runs on two parallel tracks that rarely overlap on the same record. One is the Italian popular-music session career: three decades as Enzo Jannacci's saxophonist and clarinetist, studio and arranging work for Giorgio Gaber and Adriano Celentano, Sanremo Festival orchestra direction, and backing credits behind some of Italian pop's best-known vocalists. The other is a jazz career built specifically around American swing and dixieland repertoire, expressed both as a sideman, in Lino Patruno's Milan College Jazz Society sessions behind visiting American musicians such as Billy Butterfield and Joe Venuti, and as a bandleader, first with his own recordings from the early 1990s and then with the 20-piece Paolo Tomelleri Big Band he has directed since 1993. His stated influences on the clarinet run through the swing tradition of Benny Goodman and Artie Shaw, and his big band's book leans on the Fletcher Henderson, Ellington and Basie arranging tradition. A description of his work as extending "beyond the Italian swing revival scene" through his American-musician collaborations reflects how his own sources frame him: less a revivalist recreating a past style than a working participant in the same trans-Atlantic swing and dixieland circuit that brought American musicians through Milan for decades.