Francesco Saiu is a Sardinian-born guitarist and composer, long based in the Brescia area of Lombardy, who plays both nylon-string classical guitar and electric guitar in the contemporary, improvisation-minded corner of Italian jazz. He began on guitar as a child under his father's guidance, came to jazz around the age of 20, and moved from Sardinia to Lombardy in 1997 to study at the Luca Marenzio Conservatory in Brescia with Corrado Guarino. He holds first- and second-level degrees in music and jazz guitar from Marenzio and also worked in the permanent music-research laboratories of Siena Jazz.

His early credentials came from Italian jazz competitions: the best-student scholarship at Nuoro Jazz in 2000, a finalist place for best new jazz talent at the Eddie Lang Jazz Festival the same year, a Saint Louis College of Music scholarship in 2001, third prize at the Moncalieri Jazz festival's "Incroci sonori jazz" competition in 2002 with the Francesco Saiu Trio, and a finalist place in the under-30 new-talents competition at Piacenza Jazz in 2003. His own biography lists master classes with Jim Hall, Mike Stern, Pat Metheny, Joe Lovano, Bebo Ferra, Stefano Battaglia, Gianluigi Trovesi, Franco D'Andrea, Marc Ribot, Butch Morris and Markus Stockhausen, among others; those are self-reported study credits, not recording credits.

His recorded career starts with Provvisorio (2004, Splasc(H) Records), a large-ensemble session led by Paolo Damiani with his Alea Ensemble, recorded in August 2003 and including a live track from the Sarteano Jazz Festival; Saiu plays guitar alongside trumpeter Angelo Olivieri and vocalist Chiara Liuzzi. In 2006 he made Linnas (Enthropya) with Pietro Ballestrero, a quintet record by his own account. His first record under his own name on Discogs is Nasciri (2008, Dodicilune), a quartet date recorded on July 7, 2007 at Artesuono in Cavalicco, near Udine, with pianist Stefano Battaglia, bassist Giulio Corini and drummer Fabrizio Saiu; Saiu co-produced it with Gabriele Rampino. The Italian magazine Suono, reviewing it, called it an extraordinary first work and pointed to the lyricism of the melodic writing and the free but reflective improvising with Battaglia.

The next records widened the format. Radici (2010, Dodicilune) is the debut of the Radici Ensemble, a group formed in 2008 to work on the boundary between popular and contemporary music, with Liuzzi on voice, Francesco Ganassin on clarinets, Saiu on classical guitar and Fabrizio Saiu on percussion. Quattro Elementi (2012, independent) is a duo record with pianist Oscar Del Barba under the name Minus Duet, which played the conservatory seasons of Milan, Parma, Brescia and Mantova in 2012 per his biography. Three Branches (2016, El Gallo Rojo), recorded June 14 and 15, 2015, is a drummerless trio with bass clarinetist Achille Succi and bassist Giacomo Papetti, on which Saiu plays electric guitar. Most recently he is one of thirteen musicians on Andrea Ruggeri's Musiche Invisibili (Da Vinci Jazz, 2023), a seven-movement suite after Italo Calvino's Invisible Cities, recorded live at the Salone Teresiano of the University Library of Pavia on June 21, 2017, where he plays classical and electric guitar.

Alongside performing he teaches: he is a guitar teacher at the Conservatorio G. Donizetti in Bergamo and has taught jazz guitar at the Accademia Musicale Zerootto in Cellatica since 2006 and at the Accademia Musicale Pasini in Nigoline Franciacorta since 2007. He wrote the jazz appendix and edited the harmony section on Messiaen and Bartok for Evy De Marco's I Colori della Musica (Map Edizioni, 2013). His performance work extends to poets, painters, dance and theatre, including several years as a guest of the Premio Letterario Nazionale Dessi and appearances at the Festival della Storia and the Grazia Deledda celebrations in Sardinia. His site also lists a duo project with guitarist Bebo Ferra; it is a named project on his own page, not a recording credit.

Birth date and birthplace are not publicly documented.

Saiu is a composer-guitarist whose own-name records carry original compositions, and whose sound moves between nylon-string classical guitar and electric guitar depending on the project. His records sit where jazz meets contemporary composition and free improvisation: a piano quartet with Battaglia on Nasciri, a clarinet-and-voice chamber group on Radici, a piano duo on Quattro Elementi, a drummerless trio with bass clarinet on Three Branches, and a thirteen-piece suite ensemble on Musiche Invisibili. His own biography frames his interests as spanning "the most diverse art forms," and describes collaborations across contemporary jazz, contemporary classical music and improvisation. The master-class teachers his biography lists run from the American guitar line of Jim Hall, Pat Metheny and Mike Stern to Italy's improvising scene around Battaglia, Trovesi and D'Andrea, though those are study credits rather than documented collaborations.