He also became an interesting composer on the advanced music scene, and is a conductor.

He began playing recorder at age four and piano at six, then oboe, eventually studying with Cassagnaud and Veress, both teachers at the Berne Conservatory. He transferred to Paris to study oboe with Pierlot and piano with Lefébure. In 1959 he won a first prize for oboe in the Geneva Competition and in the same year was hired as an oboist in the Basel Symphony Orchestra. Meanwhile he studied composition with Pierre Boulez form 1961 to 1963.

He started on a career as an international oboe virtuoso in 1963. His tours included solo appearances, performances with his wife, the harpist Ursula Holliger, and chamber music appearances as part of the Holliger Ensemble, a chamber group he founded. He was appointed professor of oboe at the Staatliche Musikhochschule of Freiburg in 1965.

He quickly became known as the outstanding oboist of the time. He has adopted the smoother, thinner French sound rather than the wider German quality. Even by comparison with the French sound, his tone quality is exceptionally bright. He appears to understand proper performance style on the oboe for all eras of music, and uses the proper musical approach for any music from the time of the development of the oboe as a concert instrument to the most avant garde technique. He is credited with having extended the technique of the instrument in more ways than any other oboist. Some of these techniques include harmonics, double trills, chords, and glissandos. In an interview, he has disputed this credit. Saying, "I have invented nothing," he points to instances where these techniques appeared in earlier music (such as an oboe glissando in Mahler's Third Symphony) but in fact he was the first to make use of all of them extensively. In addition, he had introduced new sounds that can only be obtained by placing a microphone inside the instrument.

He is very alert to the need to extend the repertoire of the instrument. He has been critical of oboists of the past for settling for third-rate music rather than commissioning challenging music of the great composers. He has commissioned works from Berio, Stockhausen, Penderecki, Frank Martin, Pousseur, Henze, Krenek, Jolivet, and Lutoslawski. The Lutoslawski work, a double concerto for oboe, harp, and orchestra, written for Holliger and his wife, is considered a major masterpiece.

Holliger began composing when he was young, and has compiled an extensive catalogue in many genres. His music is thoroughly influenced by Schoenberg and Webern and by Luigi Nono, an important Italian serial composer. Using Nono's tone row called the "all interval series," Holliger composed The Magical Dances for two dancers, chorus, orchestra, and tape, a work of exceptional aural density and fine nuances. He has used different Indian rhythms to represent specific poetic imagery. In Pneuma for thirty-six winds, four radios, organ, and percussion (1970) he requires the performers to make specific breathing sounds into microphones, and Cardiophonie amplifies a stethoscope attached to a solo wind player, so as to add the sound of his pulse to the music. Usually his music has very tight internal logic caused by the strict use of serial procedures, and his musical textures can range from slow, attenuated wisps of sound to combinations of instrumental sound so thick that they practically become "white noise." It is almost uniformly difficult music to listen to. ~ Joseph Stevenson