Walker starred in the musical "Till the Clouds Roll By" (1946), in which he played the popular composer Jerome Kern, which had rental receipts of over $6 million. He starred as another composer, Johannes Brahms, in "Song of Love" (1947), which co-starred Katharine Hepburn and Paul Henreid, which lost MGM over a $1 million. In between, he made a film about the construction of the atomic bomb, "The Beginning or the End" (1946), which also resulted in a loss at the box-office, and a Tracy-Hepburn drama directed by Elia Kazan, "The Sea of Grass" (1947), which was profitable.