Al Lewis, who smoked Italian cigars in real life, decided to introduce the trait
to Grandpa in order to be able to smoke whenever he wanted.

Pat Priest's mother, Ivy Baker Priest, was a former United States Treasurer.
Pat starred opposite Elvis Presley in "Easy Come, Easy Go" and, after the
movie finished filming, she bought Elvis' black Cadillac El Dorado.

Producers originally had comedian Bert Lahr in mind to portray Grandpa.