Davies' friend George Seaton loved the story so much that Seaton covered the studio's expenses in live filming during the 1946 Macy*s Thanksgiving Day Parade. All the New York shooting was done in one take because of the frigid temperatures that November, and because the parade did not allow for re-shoots. Edmund Gwenn, who plays Santa Claus in the film was Macy*s Santa that year, and the people in the crowd are actual paradegoers.
In a high-risk move, Macy*s and Gimbel's were given a "kill option" on the film to be exercised by either store at the time the final film was first privately screened. The use of either "kill option" would have required almost total re-scripting and re-shooting; fortunately, both stores embraced the film enthusiastically.
Darryl F. Zanuck loved Miracle on 34th Street so much that he had the film released in June of 1947.
Maureen O'Hara, who plays the skeptical Doris Walker, said that the cast and crew had a wonderful time working on the film, and it shows; the film was an instant hit and remains a nostalgic favorite.
Ms. O'Hara, who is known as "The Lady Who Knows Santa Claus" has said that by the time production wrapped everyone was convinced that Edmund Gwenn really was Santa Claus. The beard is genuine.