Natalie Wood turned down the role of Judith Anderson because she didn't want to work with Kirk Douglas for "personal" reasons.
The character of Anthony Anderson was loosely based on the historical figure of Peter Muhlenberg, known as the "Fighting Parson of the American Revolution".
The film was started by Alexander Mackendrick, but he left shortly after production began and was replaced by Guy Hamilton.
The play was first performed as a 'Copyright Performance' on 17 April 1897 in London, with Shaw reading the part of Rev. Anderson. He was unhappy with the play and wouldn't permit a public performance at that time. It was first shown in the United States on Broadway's Fifth Avenue Theater in New York City on 4 October 1897, and in London the following year. There were 4 Broadway revivals in the United States, the last in 1988.
The scene near the end of the movie where Gen. Burgoyne invites Richard Dudgeon and Mrs. Anderson to dine with him and his lady friend is based loosely on the historical fact that after the British surrender at Saratoga, Gen. Burgoyne and the American commander Gen. Horatio Gates and their staffs then ate a simple lunch together (shortly after 2 p.m. on Friday Oct.17, 1777).