The title was changed to "Cracking Up" so late that when the characters go to see this movie, the marquee of the theater still has the original title "Smorgasbord".
Writer Bill Richmond once said of working with Jerry Lewis: "All I do is write down everything Jerry says and then sell it back to him".
After principal photography on this film was completed, Jerry Lewis went to have triple bypass heart surgery at the Desert Springs Hospital in Las Vegas.
Jerry Lewis plays ten different roles in this movie. These included Warren Nefron, Dr. Perks, a gangster, a six year old, Speed Armeter and an elderly guru. Co-writer Bill Richmond played five different parts.