She got to know Brecht in 1922, the same year she came to Berlin. She began collaborating with him in 1924, and is listed as a co-author of The Threepenny Opera (1928). She is purported to have composed the majority of the text as well as providing a German translation of John Gay's The Beggar's Opera, on which the musical play is based, as working material for Brecht and Kurt Weill, the composer. She also wrote at least half of the Mahagonny-Songspiel, although she is uncredited. She was the main text author of the musical comedy Happy End (1929). She was in exile in the United States from 1934 to 1949; she married Paul Dessau in 1943. After Brecht's death in 1956, she published works of his at the Suhrkamp Verlag, a German publishing house, and worked as a dramaturg for the Berlin Ensemble. In 1977, a collection of her works was published under the name Julia ohne Romeo (Julia without Romeo).