Marlon Brando initially refused to go on a press tour to promote the film. The studio threatened him, as he was contractually required to promote the film, so Brando made an appearance at one press conference at which he said, "You will be unable to proceed in life unless you see Morituri." The studio released him from doing more press appearances after this sarcastic statement.
Initially, Trevor Howard was reluctant to work alongside Marlon Brando again, following their strained relationship while filming "Mutiny on the Bounty" (1962). However, since Howard only had a one scene appearance, he finally agreed.
Esther, played by Janet Margolin, uses the surname Goddard instead of her own surname Levy in order to conceal her Jewish ethnicity. This reflects the real life situation of Hollywood actress Paulette Goddard who changed her name from Marion Levy in order to downplay her own Jewish ethnicity.
The Morse code heard at the end of the movie says "CQ CQ CQ DE SS INGO (then code for a new line: BT) CARGO SHIP OUT OF . . . " (code fades as music rises). The repeated CQ's are an invitation to whoever may be listening to reply. [DE is code shorthand meaning "from"]
As Colonel Statter looks at a painting in Crain's home, he tells the colonel that it's a Kirchner. Ernst Ludwig Kirchner was a German painter, and one of the founders of Die Brücke ("The Bridge"), an influential vanguard of Expressionist painters. In the 1930s, his art was labeled as "degenerate" by the Nazis who destroyed many of his paintings. He committed suicide in 1938.