Her mother, the American translator Maria McDonald, also studied singing.

Together with Betsy's father, the poet and journalist Eugene Jolas, she founded and edited the magazine transition,[1][2] which published over ten years many of the great writers of the interwar period.

[3] After graduating from Bennington College, Jolas returned to Paris in 1946 to continue her studies at the Conservatoire national supérieur de musique, notably with Darius Milhaud and Olivier Messiaen.

[4] Her numerous works (she has been composing steadily since 1945) are written for a great variety of combinations and have been widely performed, by artists such as Kent Nagano, Anssi Karttunen, Claude Delangle, William Christie, Håkan Hardenberger, Antoine Tamestit, Nicolas Hodges, and Sir Simon Rattle, and ensembles and orchestras including the Ensemble intercontemporain, the Berlin Philharmonic, the Orchestre de Paris, the Boston Symphony Orchestra, and the BBC Symphony Orchestra.

[5] Jolas married the physician Gabriel Illouz in 1949; the pair had three children.