Gaetano Liguori was born in Naples on May 19, 1950, and made his career in Milan. He studied at the city's Giuseppe Verdi Conservatory, taking diplomas in piano and electronic composition, and began working as a jazz pianist with the bassist Giorgio Buratti. His first free-jazz experience came in the Gruppo Contemporaneo of the trumpeter Guido Mazzon, where he stayed for about two years from 1971. His father was the drummer Lino Liguori, and the two recorded together.

In 1973 he founded the Idea Trio with the bassist Roberto Del Piano and the drummer Filippo Monico. The trio played Milan's Jazz Power club and Rome's Folkstudio, and its records for the PDU label, Cile Libero, Cile Rosso (recorded April 19, 1974) and I Signori Della Guerra (1975), set free-jazz improvisation against overt political subjects such as Chile and war. In 1976 he assembled the Gaetano Liguori Collective Orchestra for a single PDU album, recorded on February 3 and 4 with a front line that included Massimo Urbani and Danilo Terenzi alongside Guido Mazzon; Urbani and Terenzi later joined an Idea Quintet whose March 1979 concert at Milan's Palazzina Liberty was released by Philology in 1999 as Live. Terenzi and Del Piano are also on Terzo Mondo (Palcoscenico, 1980), recorded live at the Milan club CIAK on November 2, 1979.

Politics stayed at the center of the work. La Cantata Rossa Per Tall El Zaatar (1977), a record about the Tall el-Zaatar massacre made with the poet and voice Giulio Stocchi, features Demetrio Stratos on vocals and was reissued on vinyl decades later. Through the 1980s his Bull Records catalogue documented solidarity projects: Tema Di Luna (1983, trio), the electronic-tape suite Tetakkon and People Of Eritrea (both 1986), ¡Qué Viva Nicaragua! (1988), and, as field recordist, a Casamance, Senegal, collection recorded in the winter of 1987-88. His own biographies list solidarity tours in Eritrea, Nicaragua, Senegal and the Sahara, among other places, and concerts in Cuba, India, Thailand, Singapore and Malaysia. In 1987 he was one of four pianists on the Fonit Cetra box set Il Pianoforte Senza Confini, taking two LP sides alongside Enrico Pieranunzi, Raimondo Campisi and Antonio Ballista, recorded live at the Piccolo Teatro di Milano.

His 1990s and 2000s records are more openly international in cast. La Nascita Della Tragedia (Linearecord, 1994) is a set of theatre music built on plays by Marlowe, Mamet, Buchner and Anna Vivarelli, with Alberto Mandarini on trumpet for its last five tracks. Ronin (Splasc(h), recorded October 13, 1999) is a suite from his multimedia concert inspired by Akira Kurosawa, with Carlo Actis Dato on saxophones and bass clarinet, Mazzon on trumpet and an insert of field recordings from Senegal, Thailand and Turkey. On L'Anima Di Un Uomo (Splasc(h), recorded June 8, 2003) he plays with Roberto Ottaviano and the Chicago drummer Hamid Drake, and on When We Were Kings (Soul Note, 2005) with drummer Andrew Cyrille and Mazzon, in four pieces that refer to Muhammad Ali's 1974 fight in Kinshasa. The Idea Trio continued alongside all this: Durante La Festa (1998), Il Comandante (2003) and Noi Credevamo (E crediamo ancora) (2011). His solo record Un Pianoforte Per I Giusti (Bull Records, 2016), made with Gariwo, the Garden of the Righteous, was recorded in the Sala Verdi of the Milan Conservatory between July and November 2015.

He taught piano at the Verdi Conservatory in Milan from 1978 to 2016, alongside Giorgio Gaslini there, and has also run improvisation workshops and master classes elsewhere. He received the discographic critics' award in 1978 and Milan's Ambrogino d'oro civic honour in 2013. He is also an author: Una storia del jazz (Marinotti, 1999, with Guido Michelone), Un pianoforte contro (Selene, 2003, with Claudio Sessa) and La mia storia del jazz (Jaca Book, 2021). Biographical sources credit him with more than 3,000 concerts and more than thirty records with the Idea Trio, and with workshops alongside Steve Lacy, Roswell Rudd and Don Cherry, and collaboration with Enrico Rava; these are reported in his own gallery biography, and no Discogs credit documents any of them.

Liguori is a free-jazz pianist for whom the music is also a public statement. The dedication printed on the Tetakkon sleeve names Cecil Taylor, Ornette Coleman, Giorgio Gaslini and Thelonious Monk alongside the electronic composer Angelo Paccagnini, Stockhausen, Schoenberg, Bartok and Stravinsky. That list matches the records: a percussive, cluster-driven piano indebted to Taylor, tape and synthesizer work from his electronic-composition training, and a piano-solo repertoire that has taken in Satie, Schoenberg, Bussotti and Monk. His Idea Trio piece "Corale Per Albert Ayler" (on the 1999 Live) acknowledges Albert Ayler. Around the free playing sits a habit of writing to an occasion, whether a country, an anniversary, a poem or a play, so that many of his records carry a dedication, a producer such as an association or a newspaper, and a cause. He has also written about jazz at book length, and his sessions with Andrew Cyrille and Hamid Drake connect his Milan free-jazz lineage to the American drummers who defined the idiom.