“I have written some harsh things in the past about Kurt Weill and his music,” wrote Blitzstein in a review of Johnny Johnson that appeared in the fall of 1936. “I wish now to write a few good things. He hasn't changed, I have.” Blitzstein found in Johnny a “fresher and more appealing” alternative to the “smart-striving social-climbing Broadway songs” with which he associated American music theater. If he considered the message in Johnny “softvoiced” or “velvet propaganda,” he acknowledged that “Weill has practically added a new form to the musical theatre. It is not opera, although it partakes of the ‘number’ form of Mozart. And it is decidedly not revue-form.”

In July of that year, Blitzstein had attended a lecture Weill gave in Trumbull, Connecticut, for the Group Theatre, the New York-based leftwing collective that premiered Johnny, his first American stage work. “I feel that I can here at last continue what I have built up in Europe,” said Weill, “that I can bring to you my experiences and be certain that you will use them in the right way, and that your experiences will be helpful to me in my efforts toward the goal which I have set for me since the beginning of my career: the creation of a musical theatre for our time.”

From July 29 to September 2, Blitzstein composed his first full-length stage work, The Cradle Will Rock, at what he later described as “white heat” to process the loss his wife, Eva Goldbeck, who had died of anorexia in May. He had already conceived and performed, however, what would become Cradle's main number, “Nickel under the Foot,” for Brecht during a gathering at the home of the music writer Minna Lederman in December of 1935. According to Lederman, Brecht walked up to the piano and encouraged Blitzstein to write “a whole play about all forms of prostitution—the press, the clergy and so on.”

Blitzstein had also begun to cultivate a relationship with Lenya. In December 1935, he heard her sing “Seeräuberjenny” in concert. Struck by her “magnetism and raw lovely voice,” he noted that “her stylized gestures seem strange because of her natural warmth; but in the strangeness lies the slight enigma which is her charm.”