The operas stood at the centre of Gál's work in the post-war years, but he was no less active in other areas. In this creative period (1919-1929) many choral works were produced, among them the Phantasien nach Gedichten von Rabindranath Tagore ('Fantasies on poems by Rabindranath Tagore', Op.5), the cantata Requiem für Mignon ('Requiem for Mignon', Op.26), Motette ('Motet') to a poem by Matthias Claudius (Op.19) and Epigramme ('Epigrams') to poems by Lessing (Op.27), both for 8-part mixed a-capella choir, and Drei Lieder nach Gedichten von Rilke ( 'Three songs to poems by Rilke', Op.31) for 3-part women's chorus with piano accompaniment.

Vocal music played an essential role from the beginning. Even as a schoolboy he went to the choir rehearsals of the Singverein of the Gesellschaft der Musikfreunde, then as a student had taken part in Mandyczewski's Sunday 'Bachiads' and together with the oboist Alexander Wunderer had been co-founder of the Vienna Bach Society in 1912. In 1927 he founded his own Madrigal Society, which was then the only choir in Vienna which performed a-capella works. Gál was considered to be "one of the first to bring about the renaissance of a-capella music-making through his own compositions." [Erwin Kroll, p.175]. He himself wrote in an essay on 'Vocal Chamber Music':

"What our musical life is in need of is ... a revival of the joy of music-making, a fresh impetus for domestic music... The glories of the a-capella epoch have largely been made available in the last few decades by new editions. Here is a treasure to be unearthed for practical music which can be compared in importance to what musical life gained from the rediscovery of the life's work of Johann Sebastian Bach. But above all there is in this area a task for the creative musicians of our own time, whose fulfilment could have an extraordinarily fruitful effect on the whole of musical development: a new vocal music is there to be created, music which, though born of the spirit of our time and using the newly acquired expressive possibilities, leads back to the long-buried sources of genuine vocal music, chamber music in the true sense of the word, which offers pleasure and stimulus not merely to listen but also to sing." ['Vokale Kammermusik', Musikblätter des Anbruch X, Vol. 9-10, 1928]

In these works one can already find full autonomy and maturity of personal style, as well as a rich variety, conditioned by the material, which gives his vocal compositions a special attraction. They also gained high recognition in the reception at the time, as the following newspaper extracts testify:

[Op.27 Epigrams ] "These madrigals count among the best that have been produced in this field in recent years" [Allgemeine Musikzeitung]

or again:

"Choral music has never been fresher and wittier, even in the heyday of the madrigal, in the 16th century." [Adolf Aber in the Leipziger Neueste Nachrichten]

There also appeared a continual stream of piano and chamber works, among them the Suite for Violoncello and Piano (Op.6), the Violin Sonata (Op.17), the Piano Trio (Op.18), the Divertimento for wind octet (Op.22), composed for the Kiel Music Festival of the Allgemeiner Deutscher Musikverein (General German Music Society) and the Second String Quartet (Op.35), which was given its first performance by the Rosé Quartet in Vienna and then (played by the Kolisch Quartet) received highest recognition at the Zürich Music Festival in 1932 as "a delightful, original, magnificently melodious and rhythmically lively piece of music from the first note to the last" [Report on the 62nd. Musicians' Congress in Zürich, Kieler Zeitung 16.6.1932].