Brück began her singing career with the Erwin Lehn Dance Orchestra, where she was noticed by pianist Horst Jankowski, who arranged a television appearance with Hans-Joachim Kulenkampff, following which she was offered a recording contract. In 1957, she had a hit with "Peter, komm heut' abend zum Hafen", a version of "Green Door", which reached #7 in the German chart. In the late 1950s and early 1960s, she made numerous TV appearances, appeared in stage musicals and toured with orchestras including those of Jankowski and Hazy Osterwald.
Following her Eurovision appearance, Brück decided to concentrate on acting, and in 1970 she starred in a 13-part series for ZDF called "Miss Molly Mill" in which she played the title role, a cleaning lady-cum-amateur detective, which was a ratings hit and regularly drew audiences of over 20 million. Since the 1970s, Brück has concentrated on performing songs with religious content. Along with fellow Eurovision veterans Katja Ebstein and Peter Horton, she is a member of the initiative "Künstler für Christus" ("Artists For Christ").