The genesis of the principal characters in The Impostors began earlier, when Stanley Tucci and Oliver Platt were acting at Yale along with Tony Shalhoub. Subsequently, Tucci and Platt teamed up as a pair of dognappers in the movie Beethoven (1992). Based on their experiences acting together, Tucci developed "The Impostors" for himself and Platt to capitalize on their physical appearance, although Tucci did not "think of us as the next Laurel and Hardy, even though we are shaped and named just like Stan and Ollie." The script for "The Impostors" was completed in late 1996, and the movie went into production by the middle of 1997.
The incident in which Sir Jeremy Burtom (Alfred Molina) slaps Mike (Matt Malloy) with a sword during a performance was based on a real-life incident in which Nicol Williamson struck a fellow actor on the buttocks with a sword during a performance of "I Hate Hamlet." Williamson also exemplified his disdain for the play and his cast-mates by breaking character and badmouthing the material on and off-stage.
There is a fair amount of commonality among the cast and crew of this movie and Big Night (1996). Oliver Platt (Maurice in this movie, and associate producer of Big Night (1996)). Stanley Tucci (director, writer, and Arthur in this movie, and director, writer, and Secondo in Big Night (1996)). Walker Jones (Maitre d' in this movie, Special Thanks in Big Night (1996)). Jack O'Connell (Stage manager in this movie, Man on Truck in Big Night (1996)). Tony Shalhoub (Voltri, First Mate in this movie, Primo in Big Night (1996)) Allison Janney (Maxine in this movie, Ann in Big Night (1996)). Isabella Rossellini (The Veiled Queen in this movie, Gabriella in Big Night (1996)). Campbell Scott (Meistrich in this movie, director, and Bob in Big Night (1996)).
Billy Connolly tells in a 1999 interview with Michael Parkinson that he had a "fart machine" on set that he used to make Oliver Platt laugh. One of the actresses (unnamed) was at first not amused until Platt demonstrated his ability to fart at will.