As part of the message the movies promotes, no one is shown smoking a cigarette throughout the entire movie. In fact, except in the black and white film that Nick Naylor (Aaron Eckhart) watches, no one is seen even holding a cigarette. Naylor holds an empty packet, The Captain (Robert Duvall) holds an (unlit) cigar, and at about the 18:35 mark as the camera is panning around the club, a man on the right can be seen putting a pipe in his mouth although it is not clear if it is lit or not.
Writer and director Jason Reitman wrote individual letters to each of the stars in the film, telling them why they would be right for the part. Every one of his first choices accepted their parts, and most thanked Reitman for his great letter.
William H. Macy (Senator Ortolan Finistirre) came up with the line, "The great state of Vermont will not apologize for its cheese." His original line was, "Why, you son of a..."
When Nick Naylor (Aaron Eckhart) and Joey Naylor (Cameron Bright) are riding the Ferris wheel, their "ice cream" is really mashed potatoes. This is because hot movie lighting causes real ice cream to melt too quickly to ensure continuity from shot to shot. The use of mashed potatoes is an old photography trick used commonly in the advertising industry (which this movie is about), and is something infinitely more desirable than the other oft-used ice cream substitutes in film or photography: Crisco or lard.
Sam Elliott wanted his character to refuse to take the money. Jason Reitman spent three hours persuading him to do the part as scripted.
Elon Musk: man who closes the car door as Aaron Eckhart's Nick Naylor gets out to board a private plane - Musk owned the plane, and was also an executive producer on the film.
Christopher Buckley: The author can be seen at the metro station reading Heather's article about Nick.