A Lorrainer, born in Meurthe - et - Moselle, Schmitt originally took music lessons in Nancy with the local composer Gustave Sandré. Subsequently (at the age of 19) he entered the Paris Conservatoire. There he studied with Gabriel Fauré, Jules Massenet, Théodore Dubois, and Albert Lavignac. In 1900 he won the Prix de Rome.

From 1929 to 1939 Schmitt worked as a music critic for Le Temps, in which role he created considerable controversy, not least for his indiscreet habit of shouting out verdicts from his seat in the hall. The music publisher Heugel went so far as to call him "an irresponsible lunatic".

Having been one of the most often performed of French composers during the first four decades of the 20th century, Schmitt afterwards fell into comparative neglect, although he continued writing music till the end (and in 1952 he became a member of the Légion d'honneur). He became the subject of attacks — both in his last years and posthumously — over his pro - German sympathies during the 1930s, and over his willingness to work for the Vichy regime later on (as indeed other eminent French musicians did, notably Alfred Cortot and Joseph Canteloube).

He died in Neuilly - sur - Seine in 1958, aged 87. The 1990s witnessed a small scale revival of his output, and an increased coverage of it on compact disc.

Schmitt wrote 138 works with opus numbers. He composed examples of most of the major forms of music, except for opera. Today his most famous pieces are La tragédie de Salome and Psaume XLVII (Psalm 47). His piano quintet in B minor, written in 1908, helped establish his reputation. Other works include a violin sonata (Sonate Libre), a late string quartet, a saxophone quartet, Dionysiaques for wind band, and two symphonies. He was part of the group known as Les Apaches. His own style, recognizably impressionistic, owed something to the example of Debussy, though it had distinct traces of Wagner and Richard Strauss also.

Schmitt composed a ballet La tragédie de Salomé in 1907 as a commission from Jacques Rouché for Loie Fuller and the Théâtre des Arts. From the original ballet score, scored for twenty instruments and lasting about an hour, Schmitt prepared a symphonic poem of the same name, half as long as the ballet score, for a much expanded orchestra. The symphonic poem version is much better known (with recordings conducted by Schmitt himself, Paul Paray, Jean Martinon, Antonio de Almeida, Marek Janowski and others), but there is also an excellent recording of the 1907 ballet score under Patrick Davin on the Marco Polo label. The rhythmic syncopations, polyrhythms, percussively treated chords, bitonality, and scoring of Schmitt's work anticipate Stravinsky's The Rite of Spring. While composing The Rite of Spring, Stravinsky acknowledged that Schmitt's ballet gave him greater joy than any work he had heard in a long time, but they fell out with each other in later years, and Stravinsky reversed his opinion of Schmitt's works.

In 1927 he was one of the ten French composers who each contributed a dance for the children's ballet L'éventail de Jeanne: he wrote the finale, a Kermesse - Valse.

Paul Sordes was a painter and a member of Les Apaches, a group of artists in early 20th century Paris whose most famous member was Maurice Ravel; it was at his home that the group regularly met on Saturdays.

Tristan Klingsor called him 'une sorte de Ravel de la palette' in an obituary, and Ravel dedicated 'Une barque sur l'océan' from the piano suite Miroirs to him.