In 1914 and 1915 Mudie appeared at the Opera House, Boston in "The Merry Wives of Windsor", "Julius Caesar", "The Merchant of Venice", and "Twelfth Night". In 1916 he appeared at the New Amsterdam Theatre, New York in "The Merry Wives of Windsor", playing Justice Shallow to the Falstaff of Sir Herbert Tree. For the next five years he appeared on Broadway and on tour in the US in modern plays, including a run playing Abraham Lincoln in a play based on the politician's life (1921), and another playing Brian Strange in A.A. Milne's "Mr Pim Passes By" (1922).