He was born into a musical family, and his first successes were as a songwriter. His first big hit was "Keep the Home Fires Burning" (1914), which was enormously popular during the First World War. His 1917 show, "Theodore & Co", was a wartime hit. After the war, Novello contributed numbers to several successful musical comedies and was eventually commissioned to write the scores of complete shows. He wrote his musicals in the style of operetta and often composed his music to the libretti of Christopher Hassall.