Originally designed by Alfred Hitchcock as an experiment in seeing how audiences would react to a non-star-driven film. He was of the opinion that oftentimes having a big star attached actually hindered the narrative flow and style of the story. He also developed the film with a view to test how American audiences would react to a more subtle brand of humor than that which they were used to.
Location filming in Vermont was hampered by heavy rainfall. Many exterior scenes were actually filmed on sets constructed in a local high school gymnasium. Much of the dialogue recorded there was inaudible due to the rainfall on the tin roof, so much post-recording was necessary.
The film was unavailable for decades because its rights (together with four other pictures of the same period) were bought back by Alfred Hitchcock and left as part of his legacy to his daughter. They've been known for years as the infamous "5 lost Hitchcocks" among film buffs, and were re-released in theaters around 1984 after a 30-year absence. The others are The Man Who Knew Too Much (1956), Rear Window (1954), Rope (1948) and Vertigo (1958).
When Music Composer Lyn Murray was working on the music score for To Catch a Thief (1955), Alfred Hitchcock was already looking for a composer for this film, which was to be his next. So Murray suggested Bernard Herrmann. This was the beginning of the long professional relationship between Hitchcock and Herrmann.
Unlike some of Hitchock's other leading ladies, Shirley MacLaine became his "eating buddy", and he took her for breakfast every day before shooting. He never propositioned her, but thought of her as "a girl who needed to be fed". After living the poverty-stricken life of a Broadway chorus girl that she had just been plucked from, it was a pleasant change for MacLaine, and as a result she gained 15 pounds during shooting. Ultimately ending in a phone call from the studio telling her to stop eating so much as she was going to "ruin her career before it had even begun".
The old car driven by the deputy sheriff is an English car with the steering wheel on the right. At one point the deputy is shown driving it on the left side of the road as in England rather than on the right.
Jack Trevor Story's original novel, published in 1949, is set in post-war England, not America in the mid-1950s. There would seem to have been some censorship problems with the adaptation; in the book, the young son (who has a different name) is the illegitimate offspring of an RAF pilot killed on a bombing raid, and Harry has married the unwed mother to prevent a stain falling on the family honor. There is also an extra character in the book - an unsavory war profiteer - who is elided from the film completely.