The scene featuring Robert Morse skipping & dancing down the street on his way to work (immediately after the "Old Ivy" fight song duet with Rudy Vallee ) was filmed on location in New York City using hidden cameras and a small earpiece to cue Morse on his timing. The various amused & astonished passersby were not extras, but rather were New Yorkers reacting genuinely to someone dancing to his own tune. It may be noted that, in typical New York fashion, no matter how odd he appeared to be virtually none of the New Yorkers paid him any notice whatsoever.
The original Broadway production of "How to Succeed in Business Without Really Trying" opened at the Forty-sixth Street Theater in New York on October 14, 1961, ran for 1417 performances and won the 1962 Tony Awards for the Best Musical and Book and was nominated for Best Score. Robert Morse (Winner of the 1962 Tony Award for Best Actor in a Musical), Rudy Vallee, Ruth Kobart and Sammy Smith recreated their stage roles for the movie version.
All of Rosemary's songs (including "Happy To Keep His Dinner Warm" and "Paris Original") were cut from the movie version. Additionally, the song "Rosemary" was shortened to only be sung by Finch, rather than being a duet between the two. To make up for this "I Believe In You" was given to her for the movie. In the stage play, she does not sing this to him, and the first time it is heard is during the scene where Finch sings it to himself in the executive washroom, but she does a brief reprise of the song after this scene. In the film, she sings the full version in an earlier scene, making Finch's washroom version the reprise.
The Mirisch Company paid $1,000,000 for the film rights, an astronomical figure in 1964.
Biggley's desk is in the shape of a question mark.