After the Spanish Civil War, Montsalvatge began work as a music critic when he joined the weekly Destino in 1942, a publication he would eventually direct in 1968 and 1975.

At the start of his career, he was strongly influenced by the twelve-tone technique and by Wagnerism, which together dominated the Catalan music scene during the period represented by his Sinfonía mediterránea of 1949.

His steady contact with the French composers Olivier Messiaen and Georges Auric led to a crucial change in his style, which soon became characterized by free polytonality (Partida, 1958).

His work ranges in scale from operas (El gato con botas, Una voz en off) to chamber music (Cuarteto indiano), in between which lie his orchestral works, such as the Desintegración morfológica de la Chacona de Bach, the Laberinto o Sinfonía de réquiem, and the prizewinning Sinfonía mediterránea and many solo piano works including the well known Sonatine pour Yvette[2] (Sonatina for Yvette) written and inspired by his young daughter at the time.

He owed his international fame chiefly to one charming and outstanding work: the Cinco canciones negras for mezzo-soprano and orchestra, a blend of Antillean rhythms and themes; among them, the best known is the Canción de cuna para dormir un negrito (Lullaby to sleep a black child).