Warren's first hit song was "Rose of the Rio Grande" (1922), with lyrics by Edgar Leslie. He wrote a succession of hit songs in the 1920s, including "I Love My Baby (My Baby Loves Me)" and "Seminola" in 1925, "Where Do You Work-a John?" and "In My Gondola" in 1926 and "Nagasaki" in 1928. In 1930, he composed the music for the song "Cheerful Little Earful" for the Billy Rose Broadway revue, "Sweet and Low", and composed the music, with lyrics by Mort Dixon and Joe Young, for the Ed Wynn Broadway revue "The Laugh Parade" in 1931.