Mayer-Mahr undertook concert tours and performed as a soloist, in a duo with Willy Burmester and in a trio with cellist Heinrich Grünfeld and violinist Bernhard Dessau, who was succeeded by Alfred Wittenberg after his death in 1923.
Among his students were in particular Manfred Gurlitt, Georg Bertram, Jascha Spivakovsky, Henry Jolles, Lotar Olias, Erwin Bodky and Róża Etkin-Moszkowska.
In 1937 he appeared at an event of the Kulturbund Deutscher Juden with the cellist Leo Rostal of the local orchestra and the concertmaster Wladislaw Waghalter and, again in 1938, for the Jüdische Winterhilfe.
In 1938 he taught the Spanish conservatory student Ursula Reig free of charge, which brought him a lawsuit from the local musicians for violation of the professional ban.
In Sweden were published Mayer-Mahr's Kåserier kring pianot[3] in 1943 and in 1947 Ernste und heitere Erlebnisse rund um das Klavier.