Maurizio Giammarco was born on October 17, 1952, in Pavia and moved to Rome as a child. He started the saxophone at 14 and, by the late 1960s, was already a working musician in Rome's jazz-adjacent rock scene, co-founding Blue Morning, one of the city's first progressive rock groups to lean toward jazz. In the early 1970s he joined an experimental jazz course that pianist and composer Giorgio Gaslini ran at Rome's Conservatorio Santa Cecilia, alongside other young players from the Roman scene including alto saxophonist Massimo Urbani. That circle put him on record for the first time: he plays soprano saxophone on Gaslini's Message (BASF, 1973, credited to Giorgio Gaslini Double), a session that also carries trumpeter Enrico Rava and Urbani. In the same year he recorded on alto saxophonist Mario Schiano's free-jazz date Sud (1973) and, the year after, on Jazz A Confronto 8, billed to Schiano and Gaslini together; he had already appeared on Jazz A Confronto 5 (1973) alongside trombonist Giancarlo Schiaffini and Urbani.

In 1975 he traveled to the United States, studying at Karl Berger's Creative Music Studio in Woodstock and privately in New York with saxophonist and clarinetist Joe Allard. The same year he recorded Davanti E Oltre La Soglia, a duo album with percussionist Andrea Centazzo, Discogs-credited to both musicians as equal leaders. Through the rest of the 1970s he moved between Rome's jazz-rock and folk-revival circles (Canzoniere Del Lazio, Perigeo Special) and studio work for Italian pop artists, a freelance thread that runs alongside his jazz career for the rest of his working life without ever displacing it. In 1980 he is the tenor saxophonist on Soft Journey, credited to "Chet Baker Meets Enrico Pieranunzi," a quartet with Chet Baker, pianist Enrico Pieranunzi, drummer Roberto Gatto and bassist Riccardo Del Fra - his first documented meeting with Baker.

His own catalogue as a leader opens with the quartet album Precisione Della Notte (Riviera Records, 1983), which he also produced. In 1984 he formed Lingomania, an electric jazz quintet with guitarist Umberto Fiorentino and Gatto on drums, joined at different points by bassists Furio Di Castri or Enzo Pietropaoli, keyboardist Danilo Rea and trumpeter Flavio Boltro. Musica Jazz's readers' and critics' polls named Lingomania Italy's best group repeatedly between 1984 and 1989, and the band recorded Riverberi (1986, with Di Castri, Gatto, Fiorentino and Boltro), Grr...Expanders (1988, with Rea and Pietropaoli) and Camminando (1989) before reuniting decades later for Lingosphere (2017, Abeat Records). He led a second quartet album, Hornithology, as producer and leader in 1988, followed by Saurian Lexicon (1991) and Love Ballads (1999, Red Record), a ballads set with pianist Art Lande, bassist Piero Leveratto and Gatto on drums.

Giammarco was a featured saxophonist, alongside Joe Lovano, on bassist Giovanni Tommaso's all-star sextet date Third Step - Good Bye 900 (Ricordi, 1998), which also carried Aldo Romano on drums, Paolo Fresu and Enrico Rava on trumpet and flugelhorn, Danilo Rea and Rita Marcotulli on piano, and Flavio Boltro alongside Fresu and Rava on trumpet. In 1989 he was the tenor saxophonist on Embraceable You, the Big Bang Orchestra album fronted by Phil Woods, with Pietropaoli, Gatto, Rea, Boltro, Fresu and trumpeter Marco Tamburini all in the personnel. He recorded Live At The Big Mama (Soul Note, 2001) as a co-billed quartet with saxophonist David Liebman, drummer Daniel Humair and Di Castri on bass.

From 2005 to 2010 he directed the Parco Della Musica Jazz Orchestra (PMJO), the resident big band of Rome's Auditorium Parco della Musica, whose trumpet section included Aldo Bassi; Giammarco led it through more than a hundred concerts in Italy and abroad and released the orchestra's Open On Sunday (Parco Della Musica Records, 2011), built from four seasons of the orchestra's own material including his own compositions. In 2008 he recorded The Auditorium Session with trumpeter Tom Harrell, guitarist Fabio Zeppetella, bassist Dario Deidda and drummer Fabrizio Sferra, playing tenor and soprano saxophone and also handling the album's mixing and mastering alongside its engineer. His later projects have moved between electric and acoustic settings: Megatones, an electronics-inflected group (Punkromatic, Columbia, 2004, which he produced; Mega Meets Microtones, 2005), the collective Tricycles (Eclectricity, Parco Della Musica Records, 2012) and Rundeep (Lights And Shades, 2012). He has led Syncotribe (later expanded to Halfplugged Syncotribe) since the late 2010s, recording So To Speak (2019, self-produced, not issued on streaming platforms per his own site), Only Human (Parco Della Musica Records, 2020, with organist/pianist Luca Mannutza, guitarist Paolo Zou, bassist Matteo Bortone and drummer Enrico Morello) and, as the Maurizio Giammarco Syncotribe Quintet, Bliss Vol. 1 (2024, Parco Della Musica Records). In 2022 he and Roberto Gatto recorded the soundtrack reissue Nudo Di Donna.

Across five decades his Discogs credits also include sideman dates with Giorgio Gaslini and Mario Schiano's circle in the early 1970s; the Paolo Damiani Ensemble's Song Tong (1997, Splasc(H)), a sextet with cellist and bassist Paolo Damiani, reedman Gianluigi Trovesi, trumpeter Kenny Wheeler, pianist Stefano Battaglia and vocalist Maria Pia De Vito; pianist Luca Mannutza and saxophonist Max Ionata's Lode 4 Joe - Tribute To Joe Henderson (2006), on which he wrote the liner notes; and, closer to home, liner notes (not a performance credit) for the Lee Konitz Quartet's Listen...Silent (2002). Alongside this jazz work he has been a prolific session saxophonist for Italian pop, with Discogs-documented credits behind Mina, Fiorella Mannoia, Miguel Bosé, Francesco De Gregori and Nada spanning the 1970s through the 2000s - a substantial freelance sideline that has run in parallel with, not in place of, his standing as a jazz bandleader.

He was named best Italian saxophonist by Fare Musica magazine in 1981 and received a RAI 1 jazz-musician award in 1984, and is included in Leonard Feather's Biographical Encyclopedia of Jazz. He teaches at Siena Jazz University and at Rome's Saint Louis College of Music.

Giammarco's catalogue spans two poles of Italian jazz rather than sitting still in one. His earliest records, cut inside Giorgio Gaslini's circle and alongside Mario Schiano and Giancarlo Schiaffini in the early 1970s, are free and avant-garde in idiom, tagged Free Jazz and Contemporary Jazz on Discogs. Lingomania, his most celebrated group, moved him toward an electric, groove-driven fusion sound built on Fender Rhodes, electric bass and guitar synthesizer, closer in feel to the period's jazz-funk than to the acoustic mainstream - Discogs tags Grr...Expanders Fusion and Camminando Avant-garde Jazz, underlining how much ground the band covered even within a few years. His own quartet albums from Precisione Della Notte through Saurian Lexicon and Love Ballads sit in a more straight-ahead, standards-and-originals post-bop mode, the setting in which he has most often appeared alongside visiting American players such as David Liebman, Phil Woods, Tom Harrell and Joe Lovano. His most recent groups, Syncotribe and Halfplugged Syncotribe, return to electric instrumentation - organ, electric guitar - filtered through a smaller, more open group sound than Lingomania's.