As many other Hubay-students neither did Gertler continue his career in Hungary, He settled in Brussels in 1928, with recommendations of his teachers, where he could improve his technique by Eugène Ysaÿe.
The program of this concert anticipated his commitment to the contemporary music: two new Swiss works, Violin Concerto of Hermann Suter and Volkmar Andreae's Rhapsody.
He recorded the complete violin works of the composer for the Supraphon label, including his two concertos, that was awarded Grand Prix du Disque in Paris (1967).
Bartók and Gertler met first in connection with the transcribing of the Sonatina for violin and piano presumably in 1926, learning at first hand the composer's performance intentions for his own music.
He made the acquaintance of many of the twentieth century’s composers, as Igor Stravinsky, Darius Milhaud, Paul Hindemith and Karl Amadeus Hartmann.
Graham Whettam commemorates the music pedagogue Gertler as „Andre Gertler was part of a link stretching back through only one intermediary teacher to another celebrated Hungarian, the violinist Joseph Joachim, and through him directly to Felix Mendelssohn.” [4] He shared his experiences gladly in his home country – he was a permanent guest professor of the International Bartók Seminars in Budapest and then in Szombathely.