[1] Ahlgrimm pursued her early piano studies from 1922 at the Musikakademie, Vienna (now the University of Music and Performing Arts Vienna), under the instruction of such notable teachers as Viktor Ebenstein (perhaps now best remembered as the piano soloist in Eroica (1949 film)), Emil von Sauer and Franz Schmidt.

Before some 600 subscribers at the preconcert lectures for four of the programs in the first Bach Cycle, Ahlgrimm was the first harpsichordist to argue the case for performing Bach's last work, The Art of Fugue, in its original form as a keyboard work, an idea also adopted at that time by her younger colleague, Gustav Leonhardt (born 1928).

Ahlgrimm was a close friend of the German composer Richard Strauss and performed a 79th birthday concert for him in Vienna's Konzerthaus (Mozart-Saal) in 1943.

She served on the juries of many European harpsichord competitions, including those at Bruges, Rome, Geneva and Leipzig.

In addition to her numerous concerts and recordings, Isolde Ahlgrimm published many articles on various aspects of performance practice.

[4][5] A Dictionary of ornamentation, left unpublished at her death, has been completed by her colleague and Viennese musicologist, Helga Scholz-Michelitsch.