He taught notable players at the Vienna Conservatory from 1877 to 1908, including 20 future orchestra members, as well as Carl Flesch and Franz Kneisel.

Born in Pest, Kingdom of Hungary,[1] Austrian Empire, Grün received his first music lessons there[2] and then studied violin privately with Joseph Böhm in Vienna.

[4] When Grün, in 1864, was not granted a permanent position with a pension because he was Jewish, Joachim quit the orchestra in solidarity.

[5] From 1877 to 1908, he was also a teacher at the Vienna Conservatory[1] and trained an entire generation in the tradition of the Viennese violin school.

[5] He also taught Carl Flesch, Rosa Hochmann,[1] Franz Kneisel,[6] Hans Wessely and Max Weißgärber.