Brooks was the daughter of a lawyer, and she danced with the Denishawn company in 1922–24 and appeared in Florenz Ziegfeld's Follies on Broadway in 1925. She made her film debut that same year, soon rising to leading roles in such Hollywood films as Howard Hawks's A Girl in Every Port (1928) and William Wellman's Beggars of Life (1928). Her performances attracted the attention of the German director G.W. Pabst (Pabst, G.W.), who cast her as the amoral, self-destructive temptress Lulu in Die Büchse der Pandora (1929; Pandora's Box). Brooks's haunting performance in this film and as the 16-year-old girl who is seduced and prostituted in Pabst's Das Tagebuch einer Verlorenen (1929; Diary of a Lost Girl) marked the summit of her career. Her innocent eroticism, along with her pale, beautiful features and bobbed brunette hair, made her both a film icon and a symbol of the disdainful flapper of the 1920s.

Brooks returned to the United States in 1930, but her intellectual independence and outspokenness repeatedly brought her into conflict with studio executives there. After appearing in small roles in several Hollywood films during the 1930s, she permanently abandoned the cinema in 1938. In her later years she wrote articles for film journals, and her literate and intelligent collection of autobiographical essays, Lulu in Hollywood, was published in 1982.