Director Vincent Sherman met with John Huston just before Huston left the project to join the Army Signal Corps and shoot documentaries for the war effort. The two directors conferred just before they were about to shoot the scene in which Leland is trapped in the movie theatre and three assassins are trying to kill him. "How does he get out?" Sherman asked. Huston replied, "That's your problem! I'm off to the war!"
As the passengers debark in New York, there is a prominent shot of the Great White Fleet's head house. This was a real shipping company. It was, and is, the popular name of the United Fruit Company's shipping line. The title "Great White Fleet" in fact derived from the name given the United States Navy's main battle fleet which circumnavigated the globe in 1907-08. Painted white, the battle fleet must have been an impressive sight. The United Fruit Company's fleet was also painted white in order to help reflect the intense heat whilst operating in the tropics.
One of the Japanese is mentioned as a member of the "Kokuryukai", or Black Dragon Society. This was a nationalist Japanese organization, formed in 1901 to protect and develop Japanese interests, initially working against Russian expansion in Asia. In the US, during the Second World War, it became a convenient scapegoat for anti-Japanese propaganda and actions.
The last-minute screenplay change from Pearl Harbor to the Panama Canal was not implausible. Until the mid 1930s US military exercises concentrated on defending the Panama Canal from air, amphibious & small craft attack and were extensively covered by the press.
The shipping company portrayed in the film is a real firm, still in business, the Nippon Yusen Kabushiki Kaisha (Japan Mail Shipping Line), or NYK Line. It is part of Mitsubishi Group and was founded in 1870. The Genoa Maru was an actual NYK Line ship.
Most of the actors playing parts as Japanese were in fact of Chinese descent; these included: Keye Luke (Steamship Line Clerk,) Richard Loo (1st Officer Miyum,) Kam Tong (Dr. Lorenz manservant Oki,) Victor Sen Yung (Joe Totsuiko...) and several others. This is not totally unexpected considering that the film was made during WWII and a good many Japanese-Americans were interned.
The film's original trailer copied the same format as the one for The Maltese Falcon (1941) (which had the same director and three of the same cast members), beginning with Sydney Greenstreet's face against an otherwise dark background as his voice narrated.
"Across the Pacific" may be the title but the narrative never actually gets there. It starts in New York City (Governors Island), moves to Canada, back to New York, and continues south along the US coast (North Atlantic Ocean) to the Caribbean Sea, where it ends at or near Balboa, Panama, still some 40 miles short of the Pacific.
The cast includes two actors who played Charlie Chan's sons in that long running series. Keye Luke played Lee Chan, Charlie Chan's Number # 1 son in the Warner Oland Chan films at Fox, and Victor Sen Young (who was also credited as Sen Young in some of his films) played Number # 2 son Tommy Chan when Sidney Toler took over the role at Monogram. Both actors also played the Chan brothers in the final Chan films in the series at Monogram when Roland Winters played Charlie Chan. They appeared together for the only time in "The Feathered Serpent" (1948), one of the last of the films in the series.
Bogart's character, Rick Leyland, calls Mary Astor's character "Precious" and "Angel" -- both of which he calls her in the Maltese Falcon. Bogart's character's name, Rick, is also his name in Casablanca .