During the course of her career, Saariaho received commissions from the Lincoln Center for the Kronos Quartet and from IRCAM for the Ensemble Intercontemporain, the BBC, the New York Philharmonic, the Salzburg Music Festival, the Théâtre du Châtelet in Paris, and the Finnish National Opera, among others.

[3] After attending the Darmstadt Summer Courses, she moved to Germany to study at the Hochschule für Musik Freiburg under Brian Ferneyhough and Klaus Huber.

She found her Freiburg teachers' emphasis on strict serialism and mathematical structures stifling, saying in an interview: You were not allowed to have pulse, or tonally oriented harmonies, or melodies.

[4]In 1980, Saariaho went to the Darmstadt Summer Courses and attended a concert of the French spectralists Tristan Murail and Gerard Grisey.

In 1982, she began work at IRCAM researching computer analyses of the sound-spectrum of individual notes produced by different instruments.

She developed techniques for computer-assisted composition, experimented with musique concrète, and wrote her first pieces combining live performance with electronics.

[7] Her works with electronics were developed in collaboration with Jean-Baptiste Barrière, a composer, multimedia artist, and computer scientist who directed the IRCAM's department of musical research from 1984 to 1987.

Nymphéa (Jardin secret III) (1987), for example, is for string quartet and live electronics and contains an additional vocal element: the musicians whisper the words of an Arseny Tarkovsky poem, Now Summer is Gone.

The basic material for the rhythmic and melodic transformations are computer-calculated in which the musical motifs gradually convert, recurring again and again.

[14]: 18 In her book on Saariaho, musicologist Pirkko Moisala [fi; sv] writes about the indeterminate nature of this composition: [Kaija said:] 'There are so many kinds of percussion instruments which I do not know.

the identity and character of the composition remains the same even when the instruments are changed; each musical idea requires certain kinds of sound color but not a particular instrument.On 1 December 2016, the Metropolitan Opera gave its first performance of L'Amour de loin, the second opera by a female composer ever to be presented by the company (the first was performed more than a century earlier, in 1903).