She is widely known for her 1954 solo recording '"Little Things Mean a Lot", a song that stayed at the U.S. number one spot for nine consecutive weeks, charted in the U.S. for almost seven months, hit #1 on the UK singles chart, and sold more than two million copies. Voted "most popular female singer" in 1954 in both "Billboard" and "Variety" polls, Kallen lost her voice at the London Palladium in 1955 at the top of her career and stopped singing before an audience for four years. After testing her voice under a pseudonym in small town venues, she ultimately returned and went on to achieve 13 top-ten career hits.