Adriano Guarnieri studied at the Conservatory in Bologna where he got his diploma in musical composition with Giacomo Manzoni and another diploma in choral music with Tito Gotti. He started his activity as a conductor as well, founding the Nuovo Ensemble Bruno Maderna in Florence.
He taught musical composition at the Milan Conservatory, Florence, Pesaro Conservatory and Bologna Conservatory.
In his earliest works, from Musica per un’azione immaginaria to L’art pour l’art?, he tries to incorporate graphical elements into the music, and in so doing, he clearly shows his structuralist approach, which only later becomes more informal. Nafshi, Recit and other compositions show a turning point in his way of composing, since he pays more attention to the form, which is thought of as a synthesis of a fluid episodic multiplicity. Through his Pierrot series he was able to reveal a "melodic" component of his music which broadens in the opera Trionfo della notte (1986–87 season at the Teatro Comunale di Bologna), which won the Premio Abbiati as the best composition of the year.
Among his later works are Romanza alla notte No. 2, for violin and orchestra (Parma, June 20, 1991), proof of the deep relationship existing between the composer and Pier Paolo Pasolini's poetics.
He dedicated to Pasolini Il glicine, for soprano, reciting voice, amplified flute and violin (Milan, July 2, 1993). In Orfeo cantando... tolse..., ten lyric actions based on text freely taken by Poliziano’s Orfeo (1994), the beauty and the musicality of Poliziano’s verses, their expressive strength and their sound, the lyric aura surrounding their words, determine the musical form, and an idea of dramaturgy which is totally internal to the music and to the spatiality it created.
His collaboration with Giovanni Raboni led to the creation of Quare tristis, for soloists, chorus, two instrumental groups, two tubas and live electronics (Biennale di Venezia, 1995). In 1999, in Strasbourg, the premiere of Pensieri canuti, cantata for soloists, chorus, two ensembles in double chorus and live electronics, again based on a text by Raboni; on April 6, 2000, at the Basilica di S.Marco in Milan, Passione secondo Matteo, linked to Pasolini's film.
On October 20, 2002, in Venice, the opera-video Medea, for soloists, chorus and orchestra, was premiered.
In 2003 Medea was awarded the prestigious Premio Abbiati by the Italian musical critic in the section dedicated to novelties.
In February 2004 in Turin La terra del tramonto was performed by the Orchestra Nazionale della RAI.
The opera Pietra di Diaspro was premiered in 2007 for the Teatro dell'Opera di Roma and Ravenna Festival.
In 2013 he has started a collaboration with Tempo Reale, the centre for music research devoted to music technology based in Florence. With the musicians and technicians of the center Guarneri has realized three music work with an intense use of live electronics, premiered and performed in Florence, Ravenna, Torino, Spoleto.