During the second half of the 1920s every year brought new successes. One can see from the tables of performances of new works published by Simrock how numerous were the performances in the late twenties: in a single year from July 1926 to June 1927 a total of 24 performances of 10 piano, chamber and choral works by Gál are recorded; for the following year, when radio broadcasts were already playing a greater role, there are 38 entries ( Simrock Jahrbuch I, 1928, p.159,160; II, 1929, p. 207, 220). We get a similar picture from the opera statistics of the Oper-Jahrbuch of Universal Edition (which then had 104 operas in its list), in which the most frequently performed operas up to the end of 1926 are entered. The Heilige Ente (with 13 theatres) is in 12th place, but in a list which contains older works, too, such as Jenufa (1901) or Weber's Oberon in Gustav Mahler's arrangement (1913), and also the recent favourites, Schilling's Mona Lisa (1915), several operas by Schreker and Korngold's Snowman (1910).

Gál likewise had notable success with orchestral works in the post-war period. Above all the Overture to a Puppet Play (Op.20) became an internationally popular concert piece and had over 100 performances in a short time, from Stockholm to Basle, under conductors such as Furtwängler, Keilberth, Szell, Weingartner and Busch. For the Symphony in D (Op.30), which was published as his 'first' (after two predecessors had been 'laid aside') he was awarded a prize by the Columbia Broadcasting Corporation on the occasion of the celebrations for the 100th anniversary of Schubert's death in 1928. Further recognition of his compositions was the award of the Art Prize of the City of Vienna in 1926.

During this period Gál also established many good relationships with colleagues and friends. A number of prominent musicians had been his friends since his school and student days in Vienna, including the conductors Erich Kleiber, Georg Szell and Carl Prohaska, and the composer Egon Kornauth. Friendships were established with, among many others, the composers Julius Bittner and Karl Weigl and the oboist Alexander Wunderer. In spite of their very different views on music, he had a good working relationship with Alban Berg and Anton von Webern, and also had dealings with the composer Erich Wolfgang Korngold.