He was the brother of the political theorist Max Adler and a key early influence on his contemporary Arnold Schoenberg.
Though self-taught, Adler for many years led a string quartet whose regular cellist was another composer-friend, Franz Schmidt.
Around this time, Adler was also the teacher of the young Hans Keller, later a musician, writer and Schoenberg-expert resident in the UK.
[2] After the Anschluss, Schoenberg tried to arrange for Adler to come to California, but he escaped instead to the United Kingdom after his visa was secured by Hans Keller's brother-in-law Roy Franey.
A biography by Shapiro includes letters, stories and memoirs gathered across twenty years of discovery, of people who recounted the central role that Dr. Oskar Adler played in Vienna's pre-Nazi cultural life before 1938 and while in exile.