This was Ralph Bellamy's ninety-ninth film, and Don Ameche's forty-ninth. This was Eddie Murphy's second film, and he joked: "Between the three of us, we've made one hundred fifty movies!"
Several funny moments in the film came about by accident. Mortimer Duke (Don Ameche) having trouble catching the money clip wasn't supposed to happen that way, but the actors kept going with it and not breaking character, so it was kept in the movie. Ophelia's "Swedish" disguise came about because Jamie Lee Curtis couldn't do the correct Austrian accent.
Ralph Bellamy (Randolph) and Don Ameche (Mortimer) make cameo appearances in Un prince à New York (1988) as the same characters; the two are now homeless, and Prince Akeem (Eddie Murphy) gives them a large amount of money to get them back off the streets.
(at around 1h 50 mins) Don Ameche's strong religious convictions made him uncomfortable with swearing. This proved to be a problem for the scene at the end of the movie, where he had to shout out "Fuck him!" to a group of Wall Street executives. When he did act out the scene, it had to be done in one take, because Ameche refused to do a second one.
In 2010, as part of the Wall Street Transparency and Accountability Act, which was to regulate financial markets, a rule was included which barred anyone from using secret inside information to corner markets, similar to what the Duke brothers tried to do in the movie. Since the movie inspired this rule, it has since become known as the Eddie Murphy Rule.
George Folsey Jr.: (at around 5 mins) The executive producer appears as the first man to greet Winthorpe at Duke & Duke. (Dan Aykroyd refers to him by his real name with the line "Morning, Folsey."
John Landis: (at around 25 mins) When Valentine is released from jail, he stands near three men in trench coats on the steps of the precinct. Landis has his back to Valentine holding a briefcase.
John Landis: [prison number] (at around 39 mins) Louis' (Dan Aykroyd's) prison number is 74745058, which is the same prison number as Jake Blues (John Belushi) in Les Blues Brothers (1980), also starring Aykroyd.
John Landis: [police] (at around 37 mins) Frank Oz has a cameo as a police officer who is checking in Winthorpe's property when he gets arrested. In Les Blues Brothers (1980), he played an officer who gives Jake Blues his property back. Oz later reprised the role in Blues Brothers 2000 (1998).
John Landis: [police] (at around 17 mins) When Billy Ray (Eddie Murphy) is cornered by the Philadelphia Police at the Heritage Club as he tries to crawl out from under the table, the police point their weapons and cock them in unison; this was previously done in Les Blues Brothers (1980), when Jake (Dan Aykroyd) and Elwood (John Belushi) were cornered as they attempted to pay the past due tax bill at the Cook County Assesors Office.
John Landis: [See You Next Wednesday] (at around 1h 10 mins) On a poster in Ophelia's apartment. The poster is actually William Wyler's Les hauts de Hurlevent (1939) starring Laurence Olivier and Merle Oberon.