The appendectomy done in this film actually happened. It was performed on the USS Silversides SS236. Pharmacist's mate Thomas Mooere removed George Platter's appendix 150 feet below the ocean's surface. Photographs of the surgery are on display where this submarine is docked, in Muskegon, Michigan, at the Great Lakes Naval Memorial and Museum.
The appendectomy operation conducted by the character Pills (William Prince) was inspired by an actual appendix operation performed aboard the submarine "Seadragon" in 1942. The real-life appendectomy was performed by 22-year-old pharmacist's mate Wheeler B. Lipes with the help of an assistant. The two were able to extract the appendix of Seaman Darrell Dean Rector under very trying conditions with limited resources and skills. They used kitchen utensils and equipment including a strainer and bent spoons as retractors; alcohol taken from torpedoes, and sterilized pajamas as surgical gowns. The sub's crew had believed that Lipes was the most qualified person to perform such a life-or-death operation, as he had apparently observed appendectomies before. Lipes was persuaded to do the operation by his fellow crewmen. The operation took place 120 feet below the surface of the South China Sea. Afterwards, Lipes' actions were criticized by US Navy doctors and the US Surgeon General even considered court-martialling him. Over 60 years later, in April 2005, Lipes finally received the US Navy Commendation Medal, two months before his death. According to the 19 April 2005 Los Angeles Times obituary of Lipes, this operation was the first ever performed in a submerged submarine.
Tony Curtis, in an interview aired on TCM, recounted the day when he went into a theater and watched this film and saw Cary Grant peer through a periscope at Tokyo Bay. That moment "took his breath away" and inspired him to become an actor. Other reports state that Grant inspired Curtis to join the navy. Both Grant and Curtis would later star together in the World War II submarine comedy Operation Petticoat (1959).
Posters incorrectly advertised the film as "Destination Tokio" despite Tokyo's proper spelling appearing in the film's on-screen title. Upon the film's release on DVD, a variation of the poster using the corrected spelling was used for the cover.
This film represents one of four movies made by Hollywood during the 1940s which were about or related to the US military's Dolittle Raid on Tokyo, Japan during World War II. The four movies (the first three considered "fictionalized") are this one, The Purple Heart (1944); Bombardier (1943) and Thirty Seconds Over Tokyo (1944), the latter being the most accurate and least fictionalized of the four.
A press release for this movie announced that "Cassidy's Children" (i.e. the children of Captain Cassidy played by Cary Grant) were portrayed by the children of this movie's director, Delmer Daves. Daughter Debby Cassidy was played by daughter Deborah Daves whilst son Michael Cassidy was played by son Michael Daves. Both children's character's first names were the same as their real first names (i.e. Debby/Deborah and Michael) and both cameo performances were uncredited.
The Copperfin submarine seen in this movie was an exact scale model of a real US Navy submarine. However, for reasons of military security, equipment and operating mechanisms were of varying kinds and varieties so the enemy could not identify accurate explicit interior details of US Navy submarines. As this movie was made during the Second World War, this filmic subterfuge was done in order to confuse America's World War II wartime enemies.
Two members of the real-life US Navy submarine the 'Wahoo' were consultants and technical advisers on this film, according to a story in the ' New York Herald Tribune '. They were crew member Andrew Lennox and Lt. Cmdt. Dudley Walker Morton.