Director Robert Wise thought Farnon was too long a surname paired with Charmian. After he had given her a list of single syllable surnames, she chose Carr. She won the role of Liesl over Geraldine Chaplin, Kim Darby, Patty Duke, Shelley Fabares, Teri Garr, Mia Farrow and Lesley Ann Warren. The film was on the whole a very happy experience for her. However, during the filming of her dance scene with Rolf in the gazebo, the costumers had forgotten to put no-slip pads on her shoes. She slid through a window of the gazebo, and she "had to complete the scene in agony".